blob: 60a08e22e41338a5f2279db75697d052a499d5f0 [file] [log] [blame]
var apply = require('./_apply'),
arrayPush = require('./_arrayPush'),
baseRest = require('./_baseRest'),
castSlice = require('./_castSlice'),
toInteger = require('./toInteger');
/** Error message constants. */
var FUNC_ERROR_TEXT = 'Expected a function';
/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeMax = Math.max;
/**
* Creates a function that invokes `func` with the `this` binding of the
* create function and an array of arguments much like
* [`Function#apply`](http://www.ecma-international.org/ecma-262/7.0/#sec-function.prototype.apply).
*
* **Note:** This method is based on the
* [spread operator](https://mdn.io/spread_operator).
*
* @static
* @memberOf _
* @since 3.2.0
* @category Function
* @param {Function} func The function to spread arguments over.
* @param {number} [start=0] The start position of the spread.
* @returns {Function} Returns the new function.
* @example
*
* var say = _.spread(function(who, what) {
* return who + ' says ' + what;
* });
*
* say(['fred', 'hello']);
* // => 'fred says hello'
*
* var numbers = Promise.all([
* Promise.resolve(40),
* Promise.resolve(36)
* ]);
*
* numbers.then(_.spread(function(x, y) {
* return x + y;
* }));
* // => a Promise of 76
*/
function spread(func, start) {
if (typeof func != 'function') {
throw new TypeError(FUNC_ERROR_TEXT);
}
start = start == null ? 0 : nativeMax(toInteger(start), 0);
return baseRest(function(args) {
var array = args[start],
otherArgs = castSlice(args, 0, start);
if (array) {
arrayPush(otherArgs, array);
}
return apply(func, this, otherArgs);
});
}
module.exports = spread;