mirror of
https://github.com/whoisclebs/lodash.git
synced 2026-01-29 14:37:49 +00:00
409 lines
13 KiB
JavaScript
409 lines
13 KiB
JavaScript
// Javascript can be so much more pleasant when it's functional -- re-implement
|
|
// a bunch of utility methods from Prototype and Steele's Functional...
|
|
window._ = {
|
|
|
|
// The cornerstone, an each implementation.
|
|
// Handles objects implementing forEach, _each, arrays, and raw objects.
|
|
each : function(obj, iterator, context) {
|
|
var index = 0;
|
|
try {
|
|
if (obj.forEach) {
|
|
obj.forEach(iterator, context);
|
|
} else if (obj.length) {
|
|
for (var i=0; i<obj.length; i++) iterator.call(context, obj[i], i);
|
|
} else if (obj.each) {
|
|
obj.each(function(value) { iterator.call(context, value, index++); });
|
|
} else {
|
|
var i = 0;
|
|
for (var key in obj) {
|
|
var value = obj[key], pair = [key, value];
|
|
pair.key = key;
|
|
pair.value = value;
|
|
iterator.call(context, pair, i++);
|
|
}
|
|
}
|
|
} catch(e) {
|
|
if (e != '__break__') throw e;
|
|
}
|
|
return obj;
|
|
},
|
|
|
|
// Return the results of applying the iterator to each element. Use Javascript
|
|
// 1.6's version of map, if possible.
|
|
map : function(obj, iterator, context) {
|
|
if (obj && obj.map) return obj.map(iterator, context);
|
|
var results = [];
|
|
_.each(obj, function(value, index) {
|
|
results.push(iterator.call(context, value, index));
|
|
});
|
|
return results;
|
|
},
|
|
|
|
// Inject builds up a single result from a list of values. Also known as
|
|
// reduce, and foldl.
|
|
inject : function(obj, memo, iterator, context) {
|
|
_.each(obj, function(value, index) {
|
|
memo = iterator.call(context, memo, value, index);
|
|
});
|
|
return memo;
|
|
},
|
|
|
|
// Return the first value which passes a truth test.
|
|
detect : function(obj, iterator, context) {
|
|
var result;
|
|
_.each(obj, function(value, index) {
|
|
if (iterator.call(context, value, index)) {
|
|
result = value;
|
|
throw '__break__';
|
|
}
|
|
});
|
|
return result;
|
|
},
|
|
|
|
// Return all the elements that pass a truth test. Use Javascript 1.6's
|
|
// filter(), if it exists.
|
|
select : function(obj, iterator, context) {
|
|
if (obj.filter) return obj.filter(iterator, context);
|
|
var results = [];
|
|
_.each(obj, function(value, index) {
|
|
if (iterator.call(context, value, index)) results.push(value);
|
|
});
|
|
return results;
|
|
},
|
|
|
|
// Return all the elements for which a truth test fails.
|
|
reject : function(obj, iterator, context) {
|
|
var results = [];
|
|
_.each(obj, function(value, index) {
|
|
if (!iterator.call(context, value, index)) results.push(value);
|
|
});
|
|
return results;
|
|
},
|
|
|
|
// Determine whether all of the elements match a truth test. Delegate to
|
|
// Javascript 1.6's every(), if it is present.
|
|
all : function(obj, iterator, context) {
|
|
iterator = iterator || function(v){ return v; };
|
|
if (obj.every) return obj.every(iterator, context);
|
|
var result = true;
|
|
_.each(obj, function(value, index) {
|
|
result = result && !!iterator.call(context, value, index);
|
|
if (!result) throw '__break__';
|
|
});
|
|
return result;
|
|
},
|
|
|
|
// Determine if at least one element in the object matches a truth test. Use
|
|
// Javascript 1.6's some(), if it exists.
|
|
any : function(obj, iterator, context) {
|
|
iterator = iterator || function(v) { return v; };
|
|
if (obj.some) return obj.some(iterator, context);
|
|
var result = false;
|
|
_.each(obj, function(value, index) {
|
|
if (result = !!iterator.call(context, value, index)) throw '__break__';
|
|
});
|
|
return result;
|
|
},
|
|
|
|
// Determine if a given value is included in the array or object,
|
|
// based on '=='.
|
|
include : function(obj, target) {
|
|
if (_.isArray(obj)) return _.indexOf(obj, target) != -1;
|
|
var found = false;
|
|
_.each(obj, function(pair) {
|
|
if (pair.value == target) {
|
|
found = true;
|
|
throw '__break__';
|
|
}
|
|
});
|
|
return found;
|
|
},
|
|
|
|
// Invoke a method with arguments on every item in a collection.
|
|
invoke : function(obj, method) {
|
|
var args = _.toArray(arguments).slice(2);
|
|
return _.map(obj, function(value) {
|
|
return (method ? value[method] : value).apply(value, args);
|
|
});
|
|
},
|
|
|
|
// Optimized version of a common use case of map: fetching a property.
|
|
pluck : function(obj, key) {
|
|
var results = [];
|
|
_.each(obj, function(value){ results.push(value[key]); });
|
|
return results;
|
|
},
|
|
|
|
// Return the maximum item or (item-based computation).
|
|
max : function(obj, iterator, context) {
|
|
if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
|
|
var result;
|
|
_.each(obj, function(value, index) {
|
|
var computed = iterator ? iterator.call(context, value, index) : value;
|
|
if (result == null || computed >= result.computed) result = {value : value, computed : computed};
|
|
});
|
|
return result.value;
|
|
},
|
|
|
|
// Return the minimum element (or element-based computation).
|
|
min : function(obj, iterator, context) {
|
|
if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
|
|
var result;
|
|
_.each(obj, function(value, index) {
|
|
var computed = iterator ? iterator.call(context, value, index) : value;
|
|
if (result == null || computed < result.computed) result = {value : value, computed : computed};
|
|
});
|
|
return result.value;
|
|
},
|
|
|
|
// Sort the object's values by a criteria produced by an iterator.
|
|
sortBy : function(obj, iterator, context) {
|
|
return _.pluck(_.map(obj, function(value, index) {
|
|
return {
|
|
value : value,
|
|
criteria : iterator.call(context, value, index)
|
|
};
|
|
}).sort(function(left, right) {
|
|
var a = left.criteria, b = right.criteria;
|
|
return a < b ? -1 : a > b ? 1 : 0;
|
|
}), 'value');
|
|
},
|
|
|
|
// Use a comparator function to figure out at what index an object should
|
|
// be inserted so as to maintain order. Uses binary search.
|
|
sortedIndex : function(array, comparator, obj) {
|
|
var low = 0, high = array.length;
|
|
while (low < high) {
|
|
var mid = (low + high) >> 1;
|
|
comparator(array[mid], obj) < 0 ? low = mid + 1 : high = mid;
|
|
}
|
|
return low;
|
|
},
|
|
|
|
// Convert anything iterable into a real, live array.
|
|
toArray : function(iterable) {
|
|
if (!iterable) return [];
|
|
if (_.isArray(iterable)) return iterable;
|
|
return _.map(iterable, function(val){ return val; });
|
|
},
|
|
|
|
// Return the number of elements in an object.
|
|
size : function(obj) {
|
|
return _.toArray(obj).length;
|
|
},
|
|
|
|
//------------- The following methods only apply to arrays. -----------------
|
|
|
|
// Get the first element of an array.
|
|
first : function(array) {
|
|
return array[0];
|
|
},
|
|
|
|
// Get the last element of an array.
|
|
last : function(array) {
|
|
return array[array.length - 1];
|
|
},
|
|
|
|
// Trim out all falsy values from an array.
|
|
compact : function(array) {
|
|
return _.select(array, function(value){ return !!value; });
|
|
},
|
|
|
|
// Return a completely flattened version of an array.
|
|
flatten : function(array) {
|
|
return _.inject(array, [], function(memo, value) {
|
|
if (_.isArray(value)) return memo.concat(_.flatten(value));
|
|
memo.push(value);
|
|
return memo;
|
|
});
|
|
},
|
|
|
|
// Return a version of the array that does not contain the specified value(s).
|
|
without : function(array) {
|
|
var values = array.slice.call(arguments, 0);
|
|
return _.select(array, function(value){ return !_.include(values, value); });
|
|
},
|
|
|
|
// Produce a duplicate-free version of the array. If the array has already
|
|
// been sorted, you have the option of using a faster algorithm.
|
|
uniq : function(array, sorted) {
|
|
return _.inject(array, [], function(memo, el, i) {
|
|
if (0 == i || (sorted ? _.last(memo) != el : !_.include(memo, el))) memo.push(el);
|
|
return memo;
|
|
});
|
|
},
|
|
|
|
// Produce an array that contains every item shared between two given arrays.
|
|
intersect : function(array1, array2) {
|
|
return _.select(_.uniq(array1), function(item1) {
|
|
return _.detect(array2, function(item2) { return item1 === item2; });
|
|
});
|
|
},
|
|
|
|
// Zip together multiple lists into a single array -- elements that share
|
|
// an index go together.
|
|
zip : function() {
|
|
var args = _.toArray(arguments);
|
|
var length = _.max(_.pluck(args, 'length'));
|
|
var results = new Array(length);
|
|
for (var i=0; i<length; i++) results[i] = _.pluck(args, String(i));
|
|
return results;
|
|
},
|
|
|
|
// If the browser doesn't supply us with indexOf (I'm looking at you, MSIE),
|
|
// we need this function. Return the position of the first occurence of an
|
|
// item in an array, or -1 if the item is not included in the array.
|
|
indexOf : function(array, item) {
|
|
if (array.indexOf) return array.indexOf(item);
|
|
var length = array.length;
|
|
for (i=0; i<length; i++) if (array[i] === item) return i;
|
|
return -1;
|
|
},
|
|
|
|
/* -------------- The following methods apply to functions -----------------*/
|
|
|
|
// Create a function bound to a given object (assigning 'this', and arguments,
|
|
// optionally). Binding with arguments is also known as 'curry'.
|
|
bind : function(func, context) {
|
|
if (!context) return func;
|
|
var args = _.toArray(arguments).slice(2);
|
|
return function() {
|
|
var a = args.concat(_.toArray(arguments));
|
|
return func.apply(context, a);
|
|
};
|
|
},
|
|
|
|
// Bind all of an object's methods to that object. Useful for ensuring that
|
|
// all callbacks defined on an object belong to it.
|
|
bindAll : function() {
|
|
var args = _.toArray(arguments);
|
|
var context = args.pop();
|
|
_.each(args, function(methodName) {
|
|
context[methodName] = _.bind(context[methodName], context);
|
|
});
|
|
},
|
|
|
|
// Delays a function for the given number of milliseconds, and then calls
|
|
// it with the arguments supplied.
|
|
delay : function(func, wait) {
|
|
var args = _.toArray(arguments).slice(2);
|
|
return window.setTimeout(function(){ return func.apply(func, args); }, wait);
|
|
},
|
|
|
|
// Defers a function, scheduling it to run after the current call stack has
|
|
// cleared.
|
|
defer : function(func) {
|
|
return _.delay.apply(_, [func, 1].concat(_.toArray(arguments).slice(1)));
|
|
},
|
|
|
|
// Returns the first function passed as an argument to the second,
|
|
// allowing you to adjust arguments, run code before and after, and
|
|
// conditionally execute the original function.
|
|
wrap : function(func, wrapper) {
|
|
return function() {
|
|
var args = [func].concat(_.toArray(arguments));
|
|
return wrapper.apply(wrapper, args);
|
|
};
|
|
},
|
|
|
|
/* ---------------- The following methods apply to objects ---------------- */
|
|
|
|
// Retrieve the names of an object's properties.
|
|
keys : function(obj) {
|
|
return _.pluck(obj, 'key');
|
|
},
|
|
|
|
// Retrieve the values of an object's properties.
|
|
values : function(obj) {
|
|
return _.pluck(obj, 'value');
|
|
},
|
|
|
|
// Extend a given object with all of the properties in a source object.
|
|
extend : function(destination, source) {
|
|
for (var property in source) destination[property] = source[property];
|
|
return destination;
|
|
},
|
|
|
|
// Create a (shallow-cloned) duplicate of an object.
|
|
clone : function(obj) {
|
|
return _.extend({}, obj);
|
|
},
|
|
|
|
// Perform a deep comparison to check if two objects are equal.
|
|
isEqual : function(a, b) {
|
|
// Check object identity.
|
|
if (a === b) return true;
|
|
// Different types?
|
|
var atype = typeof(a), btype = typeof(b);
|
|
if (atype != btype) return false;
|
|
// Basic equality test (watch out for coercions).
|
|
if (a == b) return true;
|
|
// One of them implements an isEqual()?
|
|
if (a.isEqual) return a.isEqual(b);
|
|
// Nothing else worked, deep compare the contents.
|
|
return atype === 'object' && _._isEqualContents(a, b);
|
|
},
|
|
|
|
// Objects have equal contents if they have the same keys, and all the values
|
|
// are equal (as defined by _.isEqual).
|
|
_isEqualContents : function(a, b) {
|
|
var aKeys = _.keys(a), bKeys = _.keys(b);
|
|
if (aKeys.length != bKeys.length) return false;
|
|
for (var key in a) if (!_.isEqual(a[key], b[key])) return false;
|
|
return true;
|
|
},
|
|
|
|
// Is a given value a DOM element?
|
|
isElement : function(obj) {
|
|
return !!(obj && obj.nodeType == 1);
|
|
},
|
|
|
|
// Is a given value a real Array?
|
|
isArray : function(obj) {
|
|
return Object.prototype.toString.call(obj) == '[object Array]';
|
|
},
|
|
|
|
// Is a given value a Function?
|
|
isFunction : function(obj) {
|
|
return typeof obj == 'function';
|
|
},
|
|
|
|
// Is a given variable undefined?
|
|
isUndefined : function(obj) {
|
|
return typeof obj == 'undefined';
|
|
},
|
|
|
|
// Convert any value into printable string form.
|
|
toString : function(obj) {
|
|
return obj == null ? '' : String(obj);
|
|
},
|
|
|
|
/* -------------- The following methods are utility methods --------------- */
|
|
|
|
// Generate a unique integer id (unique within the entire client session).
|
|
// Useful for temporary DOM ids.
|
|
uniqueId : function(prefix) {
|
|
var id = this._idCounter = (this._idCounter || 0) + 1;
|
|
return prefix ? prefix + id : id;
|
|
},
|
|
|
|
// Javascript templating a-la ERB, pilfered from John Resig's
|
|
// "Secrets of the Javascript Ninja", page 83.
|
|
template : function(str, data) {
|
|
var fn = new Function('obj',
|
|
'var p=[],print=function(){p.push.apply(p,arguments);};' +
|
|
'with(obj){p.push(\'' +
|
|
str
|
|
.replace(/[\r\t\n]/g, " ")
|
|
.split("<%").join("\t")
|
|
.replace(/((^|%>)[^\t]*)'/g, "$1\r")
|
|
.replace(/\t=(.*?)%>/g, "',$1,'")
|
|
.split("\t").join("');")
|
|
.split("%>").join("p.push('")
|
|
.split("\r").join("\\'")
|
|
+ "');}return p.join('');");
|
|
return data ? fn(data) : fn;
|
|
}
|
|
|
|
};
|