_define-length.js•1.3 kB
"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;
};
}