55 lines
1.3 KiB
JavaScript
55 lines
1.3 KiB
JavaScript
|
"use strict";
|
||
|
|
|
||
|
|
var toPosInt = require("../number/to-pos-integer");
|
||
|
|
|
||
|
|
var test = function (arg1, arg2) { return arg2; };
|
||
|
|
|
||
|
|
var desc, defineProperty, generate, mixin;
|
||
|
|
|
||
|
|
try {
|
||
|
|
Object.defineProperty(test, "length", {
|
||
|
|
configurable: true,
|
||
|
|
writable: false,
|
||
|
|
enumerable: false,
|
||
|
|
value: 1
|
||
|
|
});
|
||
|
|
}
|
||
|
|
catch (ignore) {}
|
||
|
|
|
||
|
|
if (test.length === 1) {
|
||
|
|
// ES6
|
||
|
|
desc = { configurable: true, writable: false, enumerable: false };
|
||
|
|
defineProperty = Object.defineProperty;
|
||
|
|
module.exports = function (fn, length) {
|
||
|
|
length = toPosInt(length);
|
||
|
|
if (fn.length === length) return fn;
|
||
|
|
desc.value = length;
|
||
|
|
return defineProperty(fn, "length", desc);
|
||
|
|
};
|
||
|
|
} else {
|
||
|
|
mixin = require("../object/mixin");
|
||
|
|
generate = (function () {
|
||
|
|
var cache = [];
|
||
|
|
return function (length) {
|
||
|
|
var args, i = 0;
|
||
|
|
if (cache[length]) return cache[length];
|
||
|
|
args = [];
|
||
|
|
while (length--) args.push("a" + (++i).toString(36));
|
||
|
|
// eslint-disable-next-line no-new-func
|
||
|
|
return new Function(
|
||
|
|
"fn",
|
||
|
|
"return function (" + args.join(", ") + ") { return fn.apply(this, arguments); };"
|
||
|
|
);
|
||
|
|
};
|
||
|
|
})();
|
||
|
|
module.exports = function (src, length) {
|
||
|
|
var target;
|
||
|
|
length = toPosInt(length);
|
||
|
|
if (src.length === length) return src;
|
||
|
|
target = generate(length)(src);
|
||
|
|
try { mixin(target, src); }
|
||
|
|
catch (ignore) {}
|
||
|
|
return target;
|
||
|
|
};
|
||
|
|
}
|