pipe.js
Version:
The client-side library which is used in BigPipe to orchestrate the pagelets.
150 lines (131 loc) • 3.36 kB
JavaScript
;
var hasOwn = Object.prototype.hasOwnProperty
, undef;
/**
* Get an accurate type check for the given Object.
*
* @param {Mixed} obj The object that needs to be detected.
* @returns {String} The object type.
* @api public
*/
function type(obj) {
return Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();
}
/**
* Iterate over a collection.
*
* @param {Mixed} collection The object we want to iterate over.
* @param {Function} iterator The function that's called for each iteration.
* @param {Mixed} context The context of the function.
* @api public
*/
function each(collection, iterator, context) {
var i = 0;
if ('array' === type(collection)) {
for (; i < collection.length; i++) {
iterator.call(context || iterator, collection[i], i, collection);
}
} else {
for (i in collection) {
if (hasOwn.call(collection, i)) {
iterator.call(context || iterator, collection[i], i, collection);
}
}
}
}
/**
* Checks if the given object is empty. The only edge case here would be
* objects. Most object's have a `length` attribute that indicate if there's
* anything inside the object.
*
* @param {Mixed} collection The collection that needs to be checked.
* @returns {Boolean}
* @api public
*/
function empty(obj) {
if (undef === obj) return false;
return size(obj) === 0;
}
/**
* Determine the size of a collection.
*
* @param {Mixed} collection The object we want to know the size of.
* @returns {Number} The size of the collection.
* @api public
*/
function size(collection) {
var x, i = 0;
if ('object' === type(collection)) {
for (x in collection) i++;
return i;
}
return +collection.length;
}
/**
* Wrap the given object in an array if it's not an array already.
*
* @param {Mixed} obj The thing we might need to wrap.
* @returns {Array} We promise!
* @api public
*/
function array(obj) {
if ('array' === type(obj)) return obj;
if ('arguments' === type(obj)) return Array.prototype.slice.call(obj, 0);
return obj // Only transform objects in to an array when they exist.
? [obj]
: [];
}
/**
* Find the index of an item in the given array.
*
* @param {Array} arr The array we search in
* @param {Mixed} o The object/thing we search for.
* @returns {Number} Index of the thing.
* @api public
*/
function index(arr, o) {
for (
var j = arr.length,
i = i < 0 ? i + j < 0 ? 0 : i + j : i || 0;
i < j && arr[i] !== o;
i++
);
return j <= i ? -1 : i;
}
/**
* Merge all given objects in to one objects.
*
* @returns {Object}
* @api public
*/
function copy() {
var result = {}
, depth = 2
, seen = [];
(function worker() {
each(array(arguments), function each(obj) {
for (var prop in obj) {
if (hasOwn.call(obj, prop) && !~index(seen, obj[prop])) {
if (type(obj[prop]) !== 'object' || !depth) {
result[prop] = obj[prop];
seen.push(obj[prop]);
} else {
depth--;
worker(result[prop], obj[prop]);
}
}
}
});
}).apply(null, arguments);
return result;
}
//
// Expose the collection utilities.
//
exports.array = array;
exports.empty = empty;
exports.index = index;
exports.copy = copy;
exports.size = size;
exports.type = type;
exports.each = each;