Amp — utility functions as individual npm modules
This page is the consolidated reference for all the amp modules in a single page for the sake of being 'cmd+f' friendly.
All modules are unit tested in a wide range of browsers (including IE6+) with a CI system composed of SauceLabs and Travis CI by using zuul and tape.
Project goals:
- Excellent, cross-browser test coverage
- Independently maintained and versioned
- Strict semver for versioning
- Try very hard to maintain APIs, ideally staying on
1.x.xversion - Try to consider the published versions "done" code
- Provide easy to remember names (by using namespacing)
- Minimize unneeded interdependencies
Many of the tests and implementations were ported from Underscore.js in order to benefit from its battle-tested code. Much props to Jeremy Ashkenas and the other underscore contributors. This project would not exist if not for them and underscore's generous MIT license.
How filesizes are calculated
To give you a rough idea of what impact a given module will have on a browserify bundle's filesize we calculate it as follows:
amp module (browserified, min + gzip)
- empty file (browserified, min + gzip)
----------------------------------------
estimated weight added to your app
However, this is still a flawed estimate since if you use multiple amp modules, the actual de-duped size will be even small since they likely share dependencies.
amp-add-class
Docs
Adds class(es) to an element.
All of the following work:
addClass(el, 'foo');
addClass(el, 'foo', 'bar');
addClass(el, ['foo', 'bar']);
Optimized for minimal DOM manipulation. The most common usecase of adding a single class will use native Element.classList if available. Otherwise, it will do a single read of el.className and only write back to it once, and only if something was actually changed.
Example Usage
var addClass = require('amp-add-class');
var element = document.querySelector('#my-el');
element.outerHTML; //=> '<div>greetings</div>';
// basic adding
addClass(element, 'oh');
element.outerHTML; //=> '<div class="oh">greetings</div>';
// adding an existing class does nothing
addClass(element, 'oh');
// add multiple at once
addClass(element, 'hello', 'there');
element.outerHTML; //=> '<div class="oh hello there">greetings</div>';
// using array
addClass(element, ['foo', 'bar']);
element.outerHTML; //=> '<div class="oh hello there foo bar">greetings</div>';
Estimated bundle size increase
~374 B (details)
Dependencies
amp-has-class
Docs
Returns true if the element has the class and false otherwise.
If the first argument is a string, it is assumed to be what you'd get from el.className. This allows it to be used repeatedly for a single element without reading from the DOM more than once.
Example Usage
var hasClass = require('amp-has-class');
var el = document.querySelector('#my-div');
el.outerHTML; //=> <div class="oh hi">hello</div>
hasClass(el, 'oh'); //=> true
hasClass(el, 'no'); //=> false
// also works with the string result of `el.className`
var className = el.className;
hasClass(className, 'oh'); //=> true
hasClass(className, 'no'); //=> false
Estimated bundle size increase
~130 B (details)
Dependencies
amp-remove-class
Docs
Removes class(es) from an element.
All of the following work:
removeClass(el, 'foo');
removeClass(el, 'foo', 'bar');
removeClass(el, ['foo', 'bar']);
Optimized for minimal DOM manipulation. The most common usecase of removing a single class will use native Element.classList if available. Otherwise, it will do a single read of el.className and only write back to it once, and only if something was actually changed.
Example Usage
var removeClass = require('amp-remove-class');
var element = document.querySelector('#my-el');
element.outerHTML; //=> '<div class="oh hello there">greetings</div>';
removeClass(element, 'oh');
element.outerHTML; //=> '<div class="hello there">greetings</div>';
// remove multiple at once
removeClass(element, 'hello', 'there');
// can also be done by passing array
removeClass(element, ['hello', 'there']);
element.outerHTML; //=> '<div class="">greetings</div>';
Estimated bundle size increase
~310 B (details)
Dependencies
amp-toggle-class
Docs
Toggles the existence of a class on an element. If the class exists it will be removed, if it doesn't it will be added.
If a condition argument is supplied, the truthiness of that condition is what determines whether the class should exist on the element or not. This simplifies common use case of an element needing a class if condition is true.
Example Usage
var toggleClass = require('amp-toggle-class');
var element = document.querySelector('#my-el');
element.outerHTML; //=> '<div>greetings</div>';
// if no condition, toggles based on presence
toggleClass(element, 'oh');
element.outerHTML; //=> '<div class="oh">greetings</div>';
// running again, will remove it
toggleClass(element, 'oh');
element.outerHTML; //=> '<div class="">greetings</div>';
// toggling based on condition
// the `condition` always wins.
// Here, the class is missing,
// but condition is falsy
// so `toggleClass` does nothing.
toggleClass(element, 'oh', false);
element.outerHTML; //=> '<div class="">greetings</div>';
Estimated bundle size increase
~595 B (details)
Dependencies
amp-bind
Docs
Bind a function to an object, meaning that whenever the function is called, the value of this will be the object. Optionally, pass arguments to the function to pre-fill them, also known as partial application.
note: If you know you're in an environment where you'll have native Function.prototype.bind (such as node.js) there's really no reason not to just use that. It even does the partial application as described above. Many JS runtimes have it these days. Notable exceptions are Phantom.js and IE8 or older.
Example Usage
var bind = require('amp-bind');
var obj = {};
var func = function (greeting, who) {
console.log(greeting, who);
console.log(this === obj);
};
var bound = bind(func, object, 'hello', 'there');
bound();
//=> 'hello there'
//=> true
Estimated bundle size increase
~305 B (details)
Dependencies
amp-debounce
Docs
Creates and returns a new debounced version of the passed function which will postpone its execution until after wait milliseconds have elapsed since the last time it was invoked. This is useful for implementing behavior that should only happen after something has stopped occuring. For example: validating an input, recalculating a layout after the window has stopped being resized, and so on.
Pass true for the immediate parameter to cause debounce to trigger the function on the leading instead of the trailing edge of the wait interval.
Example Usage
var debounce = require('amp-debounce');
var sayHi = function () {
console.log('hi! <3');
};
var debouncedGreeting = debounce(sayHi, 200);
// will only run *once* and only 200ms after last call
debouncedGreeting();
debouncedGreeting();
debouncedGreeting();
debouncedGreeting();
// *200ms pass*
//=> 'hi'
Estimated bundle size increase
~149 B (details)
Dependencies
none
amp-delay
Docs
Slightly cleaner version of setTimeout, it invokes function after specified milliseconds. But also lets you set a context in which to call it (note that this differs from underscore's implementation).
Returns the result of setTimeout so you can still use that with clearTimeout if you need to halt it for some reason.
Related: for an excellent visual explanation of event loop and how things like setTimeout actually work, watch Philip Robert's talk "What the heck is the event loop anyway?".
Example Usage
var delay = require('amp-delay');
var sayHi = function (name) {
console.log('Oh, hello there!');
};
delay(sayHi, 200);
//=> 200ms pause
//=> 'Oh, hello there!'
// with context
var obj = {
name: 'Mr. Fox',
someMethod: function () {
// here we maintain context
delay(this.otherMethod, 200, this);
},
otherMethod: function () {
// now we can still access `this`
console.log('Oh, hello there, ' + this.name + '!');
}
};
obj.someMethod();
//=> 200ms pause
//=> 'Oh, hello there, Mr. Fox!'
Estimated bundle size increase
~343 B (details)
Dependencies
amp-limit-calls
Docs
Creates a version of the function that will be run a maximum of limit times. The result of the last function call is cached and returned for any subsequent calls.
Example Usage
var limitCalls = require('amp-limit-calls');
var timesCalled = 0;
var getCount = function () {
return ++timesCalled;
}
var modified = limitCalls(getCount, 2); //=> returns modified function
console.log(modified()); //=> 1
console.log(modified()); //=> 2
console.log(modified()); //=> 2
Estimated bundle size increase
~45 B (details)
Dependencies
none
amp-once
Docs
Returns a version of the function that can only be called one time. Repeated calls to the modified function will have no effect, returning the value from the original call. Useful for initialization functions, instead of having to set a boolean flag and then check it later.
Example Usage
var once = require('amp-once');
var counter = 0;
var modified = once(function () {
console.log('called!');
return ++counter;
});
modified();
// logs out "called!"
//=> 1
// subsequent calls returns result from
// first without actually running again.
modified(); //=> 1
modified(); //=> 1
Estimated bundle size increase
~82 B (details)
Dependencies
amp-contains
Docs
Determines whether the array or object contains an item. Returns true or false. Note that in the case of an object it checks the values not key names.
Example Usage
var contains = require('amp-contains');
console.log(contains(['hi'], 'hi')); //=> true
// with objects, keys don't matter it just looks value that matches
console.log(contains({hi: 'there'}, 'there')); //=> true
console.log(contains({hi: 'there'}, hi)); //=> false
Estimated bundle size increase
~484 B (details)
Dependencies
amp-each
Docs
You can think of this as an Array.prototype.forEach that also works on objects and rather than returning undefined as the native forEach does, it returns the list/object you're iterating over.
It iterates over all items in an array or keys in an object one at a time, passing each item to the function you supply. That function's this will be the context object, you provide if you passed one as a third argument.
Your function will be called with three arguments. In the case of an Array or arguments object those items will be (item, index, list).
In the case of an object the arguments will be (value, key, list).
Example Usage
var each = require('amp-each');
var list = ['oh', 'hello', 'there'];
var obj = {name: 'Henrik', greeting: 'Oh, hello there!'};
each(list, function (item, index) {
console.log(item, index);
});
//=> 'oh', 0
//=> 'hi', 1
//=> 'there', 2
each(obj, function (value, key) {
console.log(value, key);
});
//=> 'Henrik', 'name'
//=> 'Oh, hello there!', 'greeting'
// with a context
var myContext = {thing: 'stuff'};
each([1, 2], function () {
console.log(this);
}, myContext);
//=> {thing: 'stuff'}
//=> {thing: 'stuff'}
Estimated bundle size increase
~582 B (details)
Dependencies
amp-every
Docs
Returns true if all of the values in the collection pass the function test you provide and false otherwise. Stops looping once a single failure is found.
Example Usage
var every = require('amp-every');
var isEven = function(num){
return num % 2 === 0;
};
every([0, 10, 28], isEven); //=> true
every([0, 11, 28], isEven); //=> false
Estimated bundle size increase
~865 B (details)
Dependencies
amp-filter
Docs
Looks through each value in the collection, returning an array of all the values that pass the truth test function you pass in.
Example Usage
var filter = require('amp-filter');
var isEven = function(num){
return num % 2 === 0;
};
filter([1, 2, 3, 4], isEven); //=> [2, 4]
filter({one: 1, two: 2, three: 3, four: 4}, isEven); //=> [2, 4]
Estimated bundle size increase
~919 B (details)
Dependencies
amp-map
Docs
Returns an new array of values by mapping each value in list through the function you provide (the iteratee). If passed an object instead of an array your function will be called with the arguments (value, key, object).
This works like Array.prototype.map but works for objects and works in IE < 9.
Example Usage
var map = require('amp-map');
var array = ['oh', 'hello', 'there'];
var result = map(array, function (item, index) {
console.log(item, index);
return item.length;
});
//=> 'oh', 0
//=> 'hello', 1
//=> 'there', 2
console.log(result); //=> [2, 5, 5]
// also works on objects
var obj = {
name: 'swede',
greeting: 'hej'
};
result = map(obj, function (value, key) {
console.log(value, key);
return value.length;
});
//=> 'swede', 'name'
//=> 'hej', 'greeting'
console.log(result); //=> [5, 3]
Estimated bundle size increase
~867 B (details)
Dependencies
amp-size
Docs
Return the number of values in the list or keys (if you pass it an object).
Example Usage
var size = require('amp-size');
size([1, 2, 3]); //=> 3
size({hi: 'there', oh: 'hello there'}); //=> 2
Estimated bundle size increase
~420 B (details)
Dependencies
amp-some
Docs
Returns true if any of the values in the list pass the passed in test function. Stops iterating once found.
If no test function is passed, looks for any "truthy" value.
Example Usage
var some = require('amp-some');
some([false, true]); //=> true
var isEven = function (num) {
return num % 2 === 0;
};
some([1, 3, 6, 14], isEven); //=> true
// the `14` would never be checked
// because `6` passes
Estimated bundle size increase
~861 B (details)
Dependencies
amp-difference
Docs
Returns all the values from the array that are not present in any of the other arrays.
Example Usage
var difference = require('amp-difference');
difference([1, 2, 3, 4, 5], [1, 2]); //=> [3, 4, 5]
// can also pass multiple
difference([1, 2, 3, 4, 5], [1, 2], [3]); //=> [4, 5]
Estimated bundle size increase
~1.25 kB (details)
Dependencies
amp-flatten
Docs
Flattens a nested array (the nesting can be to any depth). If you pass shallow, the array will only be flattened a single level.
Example Usage
var flatten = require('amp-flatten');
flatten([1, [2], [3, [[4]]]]);
//=> [1, 2, 3, 4];
flatten([1, [2], [3, [[4]]]], true);
//=> [1, 2, 3, [[4]]];
Estimated bundle size increase
~299 B (details)
Dependencies
amp-index-of
Docs
Returns the index at which the item can be found in the array (also works for arguments object). Returns -1 if value is not present. Unlike native implementations this won't throw an error if passed something other than an array, it'll just return -1. You can optionally pass a fromIndex as the third argument to start the search there.
Example Usage
var indexOf = require('amp-index-of');
indexOf(['oh', 'hello', 'there'], 'hello'); //=> 1
indexOf(['hi', 'there'], 'hello'); //=> -1
Estimated bundle size increase
~131 B (details)
Dependencies
amp-last
Docs
Returns the last item(s) in an array. Passing n will return the last n items in the array. Also works on arguments.
Example Usage
var last = require('amp-last');
last([1, 2, 3]); //=> 3
last([1, 2, 3], 2); //=> [2, 3]
Estimated bundle size increase
~66 B (details)
Dependencies
none
amp-range
Docs
A function to create numbered lists of integers, handy for each and map loops. start, if omitted, defaults to 0; step defaults to 1. Returns an Array of integers from start to stop, incremented (or decremented) by step, exclusive.
Note that ranges that stop before they start are considered to be zero-length instead of negative — if you'd like a negative range, use a negative step.
Example Usage
var range = require('amp-range');
range(10); //=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
range(1, 11); //=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
range(0, 30, 5); //=> [0, 5, 10, 15, 20, 25]
range(0, -10, -1); //=> [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
range(0); //=> []
Estimated bundle size increase
~85 B (details)
Dependencies
none
amp-unique
Docs
Produces a duplicate-free version of the array, (using === to test object equality, by default).
If you know in advance that the array is sorted, passing true for isSorted will run a much faster algorithm.
If you want to compute unique items based on a transformation, pass an iteratee function. If said iteratee requires custom context, you can pass that as the last argument.
Example Usage
var unique = require('amp-unique');
unique([1, 4, 2, 4, 3]); //=> [1, 4, 2, 3]
// if sorted, you can speed things up
unique([1, 1, 2, 3, 4, 4, 5], true); //=> [1, 2, 3, 4, 5]
// getting unique objects checking a property value in list
// of objects also works
var people = [
{name: 'sue'},
{name: 'max'},
{name: 'sue'}
};
// can just pass name of property as string
unique(people, 'name');
//=> [
//=> {name: 'sue'},
//=> {name: 'max'}
//=> ]
// You can use your own iterator, just return
// value to use to check uniqueness
unique(people, function (person) {
return person.name;
});
//=> [
//=> {name: 'sue'},
//=> {name: 'max'}
//=> ]
Estimated bundle size increase
~1.01 kB (details)
Dependencies
amp-clone
Docs
Create a shallow-copied clone of the object. Any nested objects or arrays will be copied by reference, not duplicated.
Example Usage
var clone = require('amp-clone');
var original = {name: 'henrik'};
var copy = clone(original); //=> {name: 'henrik'}
console.log(original === copy); //=> false
var array = ['hi', 'there'];
var copied = clone(array); //=> ['hi', 'there']
console.log(array === copied); //=> false
Estimated bundle size increase
~219 B (details)
Dependencies
amp-defaults
Docs
Fills in undefined properties in the first object with the first value present in the passed list of defaults objects.
A bit like extend except it's used to "fill in gaps" in first object with your defaults.
Returns the modified first object.
Example Usage
var defaults = require('amp-defaults');
var person = {
name: 'Joe',
favoriteColor: 'blue'
};
defaults(person, {
height: 'unknown',
age: 'unknown'
});
console.log(person);
//=>
// {
// name: 'Joe',
// favoriteColor: 'blue',
// height: 'unknown',
// age: 'unknown'
// }
Estimated bundle size increase
~118 B (details)
Dependencies
amp-extend
Docs
Copy all of the properties in the source objects over to the destination object, and return the destination object. This is done in order, so the last source will override properties of the same name in previous arguments.
Note that this is a shallow copy, meaning that nested objects won't be merged or extended.
Example Usage
var extend = require('amp-extend');
var person = {
nickname: 'The Swede'
};
var attributes = {
greeting: 'Oh, hello there!'
};
var preferences = {
food: 'Swedish Fish'
};
extend(person, attributes, preferences);
//=>
// {
// nickname: 'The Swede',
// greeting: 'Oh, hello there!',
// food: 'Swedish Fish'
// }
Estimated bundle size increase
~111 B (details)
Dependencies
amp-has
Docs
Returns true if the object contains the given key, false otherwise. Identical to object.hasOwnProperty(key), but uses Object.prototype.hasOwnProperty directly in case it's been overridden on the object itself.
Also, protects against some obscure quirks with enumerable built-ins in IE < 9.
Example Usage
var has = require('amp-has');
var obj = {
greeting: 'Oh, hello there!'
};
has(obj, 'greeting'); //=> true
has(obj, 'hasOwnProperty'); //=> false
Estimated bundle size increase
~43 B (details)
Dependencies
none
amp-invert
Docs
Returns a copy of the object where the keys have become the values and the values the keys. Your object's values should be unique and string serializable (a.k.a. JSON.stringify-able). If the values are not unique, inverting it would squash some keys, since keys in an object have to be unique.
Example Usage
var invert = require('amp-invert');
var person = {
favoriteColor: 'magenta',
favoriteFood: 'swedish pancakes'
};
invert(person);
//=>
// {
// magenta: 'favoriteColor',
// 'swedish pancakes': 'favoriteFood'
// }
Estimated bundle size increase
~429 B (details)
Dependencies
amp-keys
Docs
Retrieve all the names of the object's properties. This is much like Object.keys (in fact just uses it if it exists). But there's with one difference, you can pass a non-object and it won't throw an error. It will always return an array. So any non-objects passed will just return [].
Example Usage
var keys = require('amp-keys');
var obj = {
hi: 'there',
oh: 'hello there'
};
keys(obj); //=> ['hi', 'oh']
keys(undefined) //=> []
Estimated bundle size increase
~383 B (details)
Dependencies
amp-matches
Docs
Returns a function that will tell you if a passed in object contains all of the key/value properties present in passed attributeObject.
Example Usage
var matches = require('amp-matches');
var filter = require('amp-filter');
var list = [
{name: 'Someone', awesome: false},
{name: 'Someone Else', awesome: true},
{name: 'Paul Irish', awesome: true}
];
var awesomenessChecker = matches({awesome: true});
var awesomePeople = filter(list, awesomenessChecker);
console.log(awesomePeople);
//=> [
//=> {name: 'Someone Else', awesome: true},
//=> {name: 'Paul Irish', awesome: true}
//=> ]
Estimated bundle size increase
~520 B (details)
Dependencies
amp-pairs
Docs
Convert an object into a list of [key, value] pairs.
Example Usage
var pairs = require('amp-pairs');
var obj = {one: 1, two: 2, three: 3};
pairs(obj); //=> [["one", 1], ["two", 2], ["three", 3]]
Estimated bundle size increase
~442 B (details)
Dependencies
amp-property
Docs
Returns a function that will itself return the given propertyName of any passed-in object. Useful when iterating collections.
Example Usage
var property = require('amp-property');
var greetingGetter = property('greeting');
var person = {greeting: 'oh, hello!'};
greetingGetter(person); //=> 'oh, hello!'
Estimated bundle size increase
~27 B (details)
Dependencies
none
amp-values
Docs
Returns all the values of an object's properties as an array.
Example Usage
var values = require('amp-values');
var obj = {
hi: 'there',
hello: 'you'
};
values(obj); //=> ['there', 'you']
Estimated bundle size increase
~438 B (details)
Dependencies
amp-escape
Docs
Escapes (or unescapes) a string for insertion into HTML, by replacing &, <, >, ", ` , and ' characters with their corresponding HTML entities.
The vast majority of time you use this you just want to escape. But since 99% of the code is the same, there's also support for unescaping.
The main export is just the escape method, but we also attach escape and unescape as properties so you can use the style in second example if preferred.
Example Usage
var escape = require('amp-escape');
var htmlString = '<b>HI</b>';
var escaped = escape(htmlString); //=> '<b>HI</b>'
escape.unescape(escaped); //=> '<b>HI</b>'
// Alternately, since both `escape` and `unescape`
// are attached to the main export you can also
// follow this style:
var escaper = require('amp-escape');
// then use them both as properties of `escaper`
escaper.escape(htmlString); //=> '<b>HI</b>'
escaper.unescape(escaped); //=> '<b>HI</b>'
Estimated bundle size increase
~571 B (details)
Dependencies
amp-includes
Docs
Returns true if the first string contains the second string and false otherwise. You can also pass a startIndex as the third argument. If passed, the search will start at that index.
Example Usage
var includes = require('amp-includes');
var myString = 'Oh, hello there!';
includes(myString, 'hello'); //=> true
includes(myString, 'hello', 10); //=> false
includes(myString, 'hi'); //=> false
Estimated bundle size increase
~37 B (details)
Dependencies
none
amp-to-camel-case
Docs
Camel cases a string by removing all whitespace and - and _ characters and capitalizing first letter following those. Takes a string like "hi world" and returns it as hiWorld. If you pass true as the second argument, it will also capitalize the first letter (sometimes referred to as Pascal case).
Note that multiple adjacent whitespace or - and _ characters are removed.
Example Usage
var toCamelCase = require('amp-to-camel-case');
toCamelCase('hi there'); //=> "hiThere"
toCamelCase('oh hello there', true); //=> "OhHelloThere"
Estimated bundle size increase
~163 B (details)
Dependencies
amp-trim
Docs
Removes whitespace from both ends of the string.
Example Usage
var trim = require('amp-trim');
trim(' oh, hi there! '); //=> 'oh, hi there!'
// works for all whitespace types
trim('\n\r\t oh, hi there!'); //=> 'oh, hi there!'
Estimated bundle size increase
~43 B (details)
Dependencies
none
amp-is-arguments
Docs
Returns true if passed value is an arguments object and false for everything else.
Example Usage
var isArguments = require('amp-is-arguments');
isArguments(arguments); //=> true
isArguments([]); //=> false
Estimated bundle size increase
~88 B (details)
Dependencies
none
amp-is-array
Docs
Returns true if passed value is an Array and false for everything else. Uses native Array.isArray if available.
Example Usage
var isArray = require('amp-is-array');
isArray([]); //=> true
isArray([1, 2, 3]); //=> true
isArray(arguments); //=> false
Estimated bundle size increase
~54 B (details)
Dependencies
none
amp-is-boolean
Docs
Returns true if passed value is true or false. Returns false for everything else.
Example Usage
var isBoolean = require('amp-is-boolean');
isBoolean(true); //=> true
isBoolean(false); //=> true
isBoolean(0); //=> false
Estimated bundle size increase
~55 B (details)
Dependencies
none
amp-is-date
Docs
Returns true if passed value is a Date and false for everything else.
Example Usage
var isDate = require('amp-is-date');
isDate(new Date()); //=> true
Estimated bundle size increase
~42 B (details)
Dependencies
none
amp-is-empty
Docs
Returns true if passed an "empty" value and false for everything else.
Empty is defined as:
- empty objects:
{} - empty arrays:
[] - empty string:
'' undefinednullNaN- the number zero:
0
Example Usage
var isEmpty = require('amp-is-empty');
isEmpty({}); //=> true
isEmpty([]); //=> true
isEmpty(''); //=> true
isEmpty(0); //=> true
isEmpty(null); //=> true
isEmpty(undefined); //=> true
isEmpty(NaN); //=> true
Estimated bundle size increase
~601 B (details)
Dependencies
amp-is-function
Docs
Returns true if passed value is a Function and false for everything else.
Example Usage
var isFunction = require('amp-is-function');
isFunction(function () {}); //=> true
isFunction({}); //=> false
Estimated bundle size increase
~65 B (details)
Dependencies
none
amp-is-nan
Docs
Tests whether object passed in is a NaN. Native implementations of isNaN return true when passed undefined. So if you want to test whether NaN is exactly NaN this does that.
Example Usage
var isNan = require('amp-is-nan');
isNan(NaN); //=> true
isNan(undefined); //=> false
isNan(0); //=> false
Estimated bundle size increase
~77 B (details)
Dependencies
amp-is-null
Docs
Returns true if passed value is null and false for everything else.
Example Usage
var isNull = require('amp-is-null');
isNull(null); //=> true
isNull('anything else'); //=> false
Estimated bundle size increase
~13 B (details)
Dependencies
none
amp-is-number
Docs
Returns true if passed value is a number and false for everything else.
Example Usage
var isNumber = require('amp-is-number');
isNumber(5); //=> true
isNumber(Infinity); //=> true
isNumber('5'); //=> false
Estimated bundle size increase
~44 B (details)
Dependencies
none
amp-is-object
Docs
Returns true if passed value is an Object. Arrays and functions are objects too, while (normal) strings and numbers are not.
So this is not a strict check per JS where typeof null returns 'object'. This is a more practical runtime check that is useful for trying to find out whether you got passed an options object or a simple argument to a function.
Example Usage
var isObject = require('amp-is-object');
isObject({}); //=> true
isObject(null); //=> false
isObject('oh, hello there'); //=> false
isObject(['hi', 'there']); //=> true
// this is not something you'd normally do, but...
isObject(new String('hi')); //=> true
Estimated bundle size increase
~29 B (details)
Dependencies
none
amp-is-object-equal
Docs
Performs an optimized deep comparison between the two objects, to determine if they should be considered equal.
Example Usage
var isObjectEqual = require('amp-is-object-equal');
var swede = {name: 'Swede', greeting: ['oh', 'hello', 'there']};
var swedeClone = {name: 'Swede', greeting: ['oh', 'hello', 'there']};
// they're not the same instance
swede == swedeClone; //=> false
// but they're deep equal
isObjectEqual(swede1, swedeClone); //=> true
Estimated bundle size increase
~809 B (details)
Dependencies
amp-is-regexp
Docs
Returns true if passed value is a a regular expression and false for everything else.
Example Usage
var isRegexp = require('amp-is-regexp');
isRegexp(/oh hello there/); //=> true
isRegexp(new RegExp('oh hello there')); //=> true
Estimated bundle size increase
~45 B (details)
Dependencies
none
amp-is-string
Docs
Returns true if passed value is a string (including empty string) and false for everything else.
Example Usage
var isString = require('amp-is-string');
isString('oh, hello there!'); //=> true
isString(''); //=> true
isString(5); //=> false
Estimated bundle size increase
~40 B (details)
Dependencies
none
amp-is-undefined
Docs
Returns true if passed value is undefined and false for everything else (including other falsy values, null, and NaN).
Example Usage
var isUndefined = require('amp-is-undefined');
isUndefined(null); //=> false
isUndefined(NaN); //=> false
isUndefined(undefined); //=> true
Estimated bundle size increase
~15 B (details)
Dependencies
none
amp-iteratee
Docs
An internal function to generate callbacks that can be applied to each element in a collection, returning the desired result — either identity, an arbitrary callback, a property matcher, or a property accessor.
Used in many of the collection and array functions.
Example Usage
var iteratee = require('amp-iteratee');
var someUtil = function (array, fn, context) {
var iteratee = createIteratee(fn, context, 3);
var result = [];
for (var i = 0, l = array.length; i < l; i++) {
result[i] = iteratee(array[i], i, array);
}
return result;
};
Estimated bundle size increase
~772 B (details)
Dependencies
amp-result
Docs
Returns the value of the named property, or if it's a function invoke it with the object as context. If no such property exists, returns undefined or the defaultValue. If defaultValue is a function it will be executed and its result returned.
Example Usage
var result = require('amp-result');
var obj = {
hi: 'there',
oh: function () {
return 'hello there'
}
};
result(obj, 'hi'); //=> 'there'
result(obj, 'oh'); //=> 'hello there'
result(obj, 'nothing', 'wat'); //=> 'wat'
Estimated bundle size increase
~136 B (details)
Dependencies
amp-unique-id
Docs
Generates a simple integer-based unique ID string. This is not a uuid, it's for simpler things like ids for DOM elements or client instances. Its uniqueness is only guaranteed by the fact that it's a single, global, always incremented counter. If a prefix is passed, the id will be appended to it.
In order to ensure uniqueness in the case where two instances of this module is required, we keep the counter variable attached to window or global (in the case of node).
Example Usage
var uniqueId = require('amp-unique-id');
uniqueId(); //=> "1"
uniqueId('hi_'); //=> "hi_2"
Estimated bundle size increase
~95 B (details)
Dependencies
none
amp-create-callback
Docs
Internal amp utility for creating callbacks used in looping functions such as map and filter (mainly used internally). Having a known argument count makes it more optimizable by browsers.
Example Usage
var createCallback = require('amp-create-callback');
var callback = createCallback(function () {
// something
}, context, 3);
[1, 2, 3].map(callback);
Estimated bundle size increase
~99 B (details)
Dependencies
none
amp-internal-flatten
Docs
An internal flatten implementation for re-use.
Takes following args:
value: initial arrayshallow: whether to flatten recursively or just one levelstrict: if strict istrueit won't keep any values other than arrays an argumentsoutput: array or array-like object we're pushing to and will return
Example Usage
var internalFlatten = require('amp-internal-flatten');
var arr = [1, [1], [[1]], 'something'];
// shallow
internalFlatten(arr, true, false, []);
//=> [1, 1, [1], 'something'];
// recursive
internalFlatten(arr, false, false, []);
//=> [1, 1, 1, 'something'];
// recursive + strict
// these options *always* will
// result an empty array as output
internalFlatten(arr, false, true, []);
//=> [];
// shallow + strict
// any non-arrays are removed
// but only run through once
// so only 2ns and 3rd args make it
// but are flattened one level
internalFlatten(arr, true, true, []);
//=> [1, [1]];
Estimated bundle size increase
~261 B (details)