no-import-assign

Disallow assigning to imported bindings

ES 模块对导入的绑定的更新会导致运行时错误。

规则细节

这条规则对导入的绑定的分配、增量和减量发出警告。

使用此规则的错误示例：

/*eslint no-import-assign: "error"*/

import mod, { named } from "./mod.mjs"
import * as mod_ns from "./mod.mjs"

mod = 1          // ERROR: 'mod' is readonly.
named = 2        // ERROR: 'named' is readonly.
mod_ns.named = 3 // ERROR: The members of 'mod_ns' are readonly.
mod_ns = {}   // ERROR: 'mod_ns' is readonly.
// Can't extend 'mod_ns'
Object.assign(mod_ns, { foo: "foo" }) // ERROR: The members of 'mod_ns' are readonly.
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使用此规则的正确示例：

/*eslint no-import-assign: "error"*/

import mod, { named } from "./mod.mjs"
import * as mod_ns from "./mod.mjs"

mod.prop = 1
named.prop = 2
mod_ns.named.prop = 3

// Known Limitation
function test(obj) {
    obj.named = 4 // Not errored because 'obj' is not namespace objects.
}
test(mod_ns) // Not errored because it doesn't know that 'test' updates the member of the argument.
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何时不用

如果你不希望被通知修改导入的绑定，你可以禁用这个规则。

Handled by TypeScript

It is safe to disable this rule when using TypeScript because TypeScript's compiler enforces this check.

注意编译器不会捕获 Object.assign() 的情况。因此，如果你在代码库中使用 Object.assign()，这个规则仍然会提供一些价值。

Version

This rule was introduced in ESLint v6.4.0.

Resources

• Rule source
• Tests source