What is this in a plain function call 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.
Explore This Question
Search for additional explanations using these tools:
More FAQs in Common this Keyword Interview Questions in JavaScript
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.
new binding (highest) > explicit binding (bind/call/apply) > implicit binding (method call) > default binding (plain call). Arrow functions are an exception: they use lexical this and ignore all of these.
Still have questions?
Browse all our FAQs or reach out to our support team