How Does \'options = options || {}\' Work in JavaScript?

Understanding the Enigma of "options = options || {}" in JavaScript

The enigmatic JavaScript syntax, "options = options || {}" has left many developers scratching their heads. This snippet serves a specific purpose: initializing object parameters with default values.

Consider the following function:

function test (options) {
  options = options || {};
}

When calling this function without arguments, "options" will assume an empty object by default. This is achieved through the "Logical OR (||)" operator.

The "Logical OR" operator assesses two operands. If the first operand is "falsy" (equivalent to 0, null, undefined, empty string, NaN, or false), the operator returns the second operand.

In our case, if "options" is not provided or is "falsy," the operator assigns an empty object to it. This effectively sets a default value for the "options" parameter.

An ES6 Evolution: Default Function Parameters

With the advent of ES6, JavaScript introduced a cleaner solution for setting default parameters:

function test (options = {}) {
  //...
}

Here, the "options" parameter is assigned the default value {} if no arguments are provided or if explicitly set to "undefined." Unlike the "Logical OR" approach, other "falsy" values will not trigger the default value.

This simplified syntax offers greater clarity and consistency in codebase maintenance.

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