javascript declare key in function code example

Example 1: how to add field to object in js

// original object { key1: "a", key2: "b"}
var obj = {
    key1: "a",
    key2: "b"
};

// adding new filed - you can use 2 ways
obj.key3 = "c"; // static
// or
obj["key3"] = "c"; // dynamic - 'key3' can be a variable
console.log(obj) // {key1: "a", key2: "b", key3: "c" }

Example 2: javascript object string property

// Also useful for dynamic strings, e.g. `thing-${variable}`
myObject['thing'] = true;