require-array-join-separator

📝 Enforce using the separator argument with Array#join().

💼 This rule is enabled in the following configs: ✅ recommended, ☑️ unopinionated.

🔧 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.

Examples

// ❌
const string = array.join();

// ✅
const string = array.join(',');

// ✅
const string = array.join('|');

// ❌
const string = Array.prototype.join.call(arrayLike);

// ✅
const string = Array.prototype.join.call(arrayLike, '');

// ❌
const string = [].join.call(arrayLike);

// ✅
const string = [].join.call(arrayLike, '\n');