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contains

Check if a key exists in the object.

{a: 1, b: 2}.contains("a"); // true
{a: 1, b: 2}.contains("c"); // false

Syntax​

contains(key)

Returns​

A boolean indicating whether the key exists or not.

Notes​

  • Use this to safely check whether a key exists or not (accessing with [] or . will throw an internal error when the key doesn't exist).