如何覆盖 JavaScript 函数
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How to override a JavaScript function
提问by Riz
I'm trying to override a built in parseFloatfunction in JavaScript.
我正在尝试覆盖JavaScript 中的内置parseFloat函数。
How would I go about doing that?
我该怎么做呢？
回答by David Waters
var origParseFloat = parseFloat;
parseFloat = function(str) {
alert("And I'm in your floats!");
return origParseFloat(str);
}
回答by Rocket Hazmat
You can override any built-in function by just re-declaring it.
您可以通过重新声明任何内置函数来覆盖它。
parseFloat = function(a){
alert(a)
};
Now parseFloat(3)will alert 3.
现在parseFloat(3)将警报 3。
回答by Anastasios Selmanis
You could override it or preferably extendit's implementation like this
您可以覆盖它或最好像这样扩展它的实现
parseFloat = (function(_super) {
return function() {
// Extend it to log the value for example that is passed
console.log(arguments[0]);
// Or override it by always subtracting 1 for example
arguments[0] = arguments[0] - 1;
return _super.apply(this, arguments);
};
})(parseFloat);
And call it as you would normally call it:
并像通常那样称呼它：
var result = parseFloat(1.345); // It should log the value 1.345 but get the value 0.345
回答by Kyle Wild
You can do it like this:
你可以这样做：
alert(parseFloat("1.1531531414")); // alerts the float
parseFloat = function(input) { return 1; };
alert(parseFloat("1.1531531414")); // alerts '1'
Check out a working example here: http://jsfiddle.net/LtjzW/1/
在此处查看一个工作示例：http: //jsfiddle.net/LtjzW/1/
