no-implicit-coercion

禁止速记类型转换

一些该规则报告的问题可以通过 --fix 命令行选项 自动修复

在 JavaScript 中，有很多不同的方法可以转换值类型。其中一些可能难以阅读和理解。

如：

var b = !!foo;
var b = ~foo.indexOf(".");
var n = +foo;
var n = 1 * foo;
var s = "" + foo;
foo += ``;

这些可以替换为以下代码：

var b = Boolean(foo);
var b = foo.indexOf(".") !== -1;
var n = Number(foo);
var n = Number(foo);
var s = String(foo);
foo = String(foo);

规则详情

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选项

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boolean

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/*eslint no-implicit-coercion: "error"*/

var b = !!foo;
var b = ~foo.indexOf(".");
// bitwise not is incorrect only with `indexOf`/`lastIndexOf` method calling.

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/*eslint no-implicit-coercion: "error"*/

var b = Boolean(foo);
var b = foo.indexOf(".") !== -1;

var n = ~foo; // This is a just bitwise not.

number

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/*eslint no-implicit-coercion: "error"*/

var n = +foo;
var n = 1 * foo;

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/*eslint no-implicit-coercion: "error"*/

var n = Number(foo);
var n = parseFloat(foo);
var n = parseInt(foo, 10);

var n = foo * 1/4; // `* 1` is allowed when followed by the `/` operator

string

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/*eslint no-implicit-coercion: "error"*/

var s = "" + foo;
var s = `` + foo;
foo += "";
foo += ``;

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/*eslint no-implicit-coercion: "error"*/

var s = String(foo);
foo = String(foo);

disallowTemplateShorthand

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/*eslint no-implicit-coercion: ["error", { "disallowTemplateShorthand": true }]*/

var s = `${foo}`;

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/*eslint no-implicit-coercion: ["error", { "disallowTemplateShorthand": true }]*/

var s = String(foo);

var s = `a${foo}`;

var s = `${foo}b`;

var s = `${foo}${bar}`;

var s = tag`${foo}`;

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/*eslint no-implicit-coercion: ["error", { "disallowTemplateShorthand": false }]*/

var s = `${foo}`;

allow

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/*eslint no-implicit-coercion: [2, { "allow": ["!!", "~"] } ]*/

var b = !!foo;
var b = ~foo.indexOf(".");

何时不使用

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