How do you approach this questions in a JavaScript interview?
Identify the call type (plain, method, call/apply/bind, new, or arrow), apply the precedence rules, account for strict mode (plain calls give undefined), and remember that arrows use lexical this regardless of call type.
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More FAQs in Common this Keyword Interview Questions in JavaScript
In non-strict mode, this is the global object (window). In strict mode, this is undefined. This is default binding, the lowest precedence rule.
this is lost. Calling const fn = obj.method; fn() is a plain call, so this is the global object or undefined, not obj. Fix with .bind(obj) or an arrow wrapper.
An arrow inside a constructor inherits this from the constructor's scope, where this is the new instance. This is why arrows fix the setTimeout-in-constructor bug.
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