no-new-func.md

规则名	规则类型
no-new-func	suggestion

It's possible to create functions in JavaScript from strings at runtime using the Function constructor, such as:

var x = new Function("a", "b", "return a + b");
var x = Function("a", "b", "return a + b");
var x = Function.call(null, "a", "b", "return a + b");
var x = Function.apply(null, ["a", "b", "return a + b"]);
var x = Function.bind(null, "a", "b", "return a + b")();

This is considered by many to be a bad practice due to the difficulty in debugging and reading these types of functions. In addition, Content-Security-Policy (CSP) directives may disallow the use of eval() and similar methods for creating code from strings.

规则详解

This error is raised to highlight the use of a bad practice. By passing a string to the Function constructor, you are requiring the engine to parse that string much in the way it has to when you call the eval function.

此规则的 错误 代码实例：

/*eslint no-new-func: "error"*/

var x = new Function("a", "b", "return a + b");
var x = Function("a", "b", "return a + b");
var x = Function.call(null, "a", "b", "return a + b");
var x = Function.apply(null, ["a", "b", "return a + b"]);
var x = Function.bind(null, "a", "b", "return a + b")();
var f = Function.bind(null, "a", "b", "return a + b"); // assuming that the result of Function.bind(...) will be eventually called.

此规则的 正确 代码实例：

::: correct

/*eslint no-new-func: "error"*/

var x = function (a, b) {
    return a + b;
};

禁用建议

In more advanced cases where you really need to use the Function constructor.