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Life, JavaScript
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众所周知，JS原生提供一个`Function.prototype.bind`函数。 面试中经常会遇到这个函数是怎么实现的问题，下面尝试解答下 假设你要实现一个myBind函数，下面的代码里给出了myBind的实现和具体的使用 ``` Function.prototype.myBind = function(context, ...args){ // 因为这里在Function.prototype上定义的，this就是函数本身，即test const originalFunc = this; return function (...moreArgs) { const symbol = Symbol.for("temp"); context[symbol] = originalFunc; const result = context[symbol](...args, ...moreArgs); delete context[symbol] return result; } } function test(count1, count2) { console.log(this.name + " has " + count1 + " apples and " + count2 + " oranges"); } const person = { name: "oliver" }; // 这里绑定了this和123，但是test函数还有count2这个参数，下面的例子中会把那个参数也用上 const boundedFunc = test.myBind(person, 123); boundedFunc(456); // 应该打印 oliver has 123 apples and 456 oranges ```
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