61 lines
1.6 KiB
JavaScript
61 lines
1.6 KiB
JavaScript
var apply = require('./_apply'),
|
|
arrayMap = require('./_arrayMap'),
|
|
baseIteratee = require('./_baseIteratee'),
|
|
baseRest = require('./_baseRest');
|
|
|
|
/** Error message constants. */
|
|
var FUNC_ERROR_TEXT = 'Expected a function';
|
|
|
|
/**
|
|
* Creates a function that iterates over `pairs` and invokes the corresponding
|
|
* function of the first predicate to return truthy. The predicate-function
|
|
* pairs are invoked with the `this` binding and arguments of the created
|
|
* function.
|
|
*
|
|
* @static
|
|
* @memberOf _
|
|
* @since 4.0.0
|
|
* @category Util
|
|
* @param {Array} pairs The predicate-function pairs.
|
|
* @returns {Function} Returns the new composite function.
|
|
* @example
|
|
*
|
|
* var func = _.cond([
|
|
* [_.matches({ 'a': 1 }), _.constant('matches A')],
|
|
* [_.conforms({ 'b': _.isNumber }), _.constant('matches B')],
|
|
* [_.stubTrue, _.constant('no match')]
|
|
* ]);
|
|
*
|
|
* func({ 'a': 1, 'b': 2 });
|
|
* // => 'matches A'
|
|
*
|
|
* func({ 'a': 0, 'b': 1 });
|
|
* // => 'matches B'
|
|
*
|
|
* func({ 'a': '1', 'b': '2' });
|
|
* // => 'no match'
|
|
*/
|
|
function cond(pairs) {
|
|
var length = pairs == null ? 0 : pairs.length,
|
|
toIteratee = baseIteratee;
|
|
|
|
pairs = !length ? [] : arrayMap(pairs, function(pair) {
|
|
if (typeof pair[1] != 'function') {
|
|
throw new TypeError(FUNC_ERROR_TEXT);
|
|
}
|
|
return [toIteratee(pair[0]), pair[1]];
|
|
});
|
|
|
|
return baseRest(function(args) {
|
|
var index = -1;
|
|
while (++index < length) {
|
|
var pair = pairs[index];
|
|
if (apply(pair[0], this, args)) {
|
|
return apply(pair[1], this, args);
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
module.exports = cond;
|