no-import-assign

An import is a read-only view of what the other module exports. Assigning to it throws a TypeError when the line runs. The members of a namespace import (import * as name) are read-only too.

This rule is on by default in JavaScript files. It's off in TypeScript files, where TypeScript reports the same mistake.

Configure

On by default as an error. To turn it off:

[lint.rules]
"no-import-assign" = "off" # or "warn"

Examples

Reported:

import config, { retries } from "./config.js";
import * as settings from "./settings.js";

config = {};
retries += 1;
settings.debug = true;
delete settings.debug;
Object.assign(settings, { debug: true });

Not reported. The object that a default or a named import points to is an ordinary object, so you can change its properties. To change a variable in another module, call a function that the module exports for that purpose:

import config, { setRetries } from "./config.js";

config.debug = true;
setRetries(3);