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Enforce using the separator argument with Array#join() ​

💼 This rule is enabled in the ✅ recommended config.

🔧 This rule is automatically fixable by the --fix CLI option.

It's better to make it clear what the separator is when calling Array#join(), instead of relying on the default comma (',') separator.

Fail ​

js
const string = array.join();
js
const string = Array.prototype.join.call(arrayLike);
js
const string = [].join.call(arrayLike);

Pass ​

js
const string = array.join(',');
js
const string = array.join('|');
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const string = Array.prototype.join.call(arrayLike, '');
js
const string = [].join.call(arrayLike, '\n');

Released under the Apache License 2.0.