function.toString
该?toString()方法返回一个表示当前函数源代码的字符串。
语法
function.toString()返回值
表示函数源代码的字符串。
描述
在函数需要转换为字符串时，通常会自动调用函数的?toString 方法。
如果它的值对象不是一个函数对象，该toString()方法将抛出一个TypeError异常（“Function.prototype.toString called on incompatible object”）。例如，它也会抛出thisFunctionProxy对象。
Function.prototype.toString.call('foo'); // TypeError
var proxy = new Proxy(function() {}, {});
Function.prototype.toString.call(proxy); // TypeError如果toString()在ECMAScript代码中未定义的内置函数对象上调用方法，则toString返回一个本地函数字符串，如下所示：
Math.abs.toString();
"function abs() {
??? [native code]
}"规范
Specification | Status | Comment |
|---|---|---|
ECMAScript 1st Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.1. |
ECMAScript 2015 (6th Edition, ECMA-262)The definition of 'Function.prototype.toString' in that specification. | Standard | Added more specific requirements for the string representation. |
Function.prototype.toString revision | Draft | Standardizes native function string, line endings. |
ECMAScript Latest Draft (ECMA-262)The definition of 'Function.prototype.toString' in that specification. | Living Standard | ? |
浏览器兼容性
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Revised support | ? | ? | 54.0 (54.0) | ? | ? | ? |
Feature | Android | Chrome for Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Revised support | ? | ? | ? | 54.0 (54.0) | ? | ? | ? |
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