Function unwrap_pattern

packages/svelte/src/compiler/utils/ast.js:89–129

(pattern, nodes = [])

 * @returns {Array<ESTree.Identifier | ESTree.MemberExpression>}
 */
export function unwrap_pattern(pattern, nodes = []) {
	switch (pattern.type) {
		case 'Identifier':
			nodes.push(pattern);
			break;

		case 'MemberExpression':
			// member expressions can be part of an assignment pattern, but not a binding pattern
			// see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#binding_and_assignment
			nodes.push(pattern);
			break;

		case 'ObjectPattern':
			for (const prop of pattern.properties) {
				if (prop.type === 'RestElement') {
					unwrap_pattern(prop.argument, nodes);
				} else {
					unwrap_pattern(prop.value, nodes);
				}
			}

			break;

		case 'ArrayPattern':
			for (const element of pattern.elements) {
				if (element) unwrap_pattern(element, nodes);
			}

			break;

		case 'RestElement':
			unwrap_pattern(pattern.argument, nodes);
			break;

		case 'AssignmentPattern':
			unwrap_pattern(pattern.left, nodes);
			break;
	}

	return nodes;
}

/**
 * Extracts all identifiers from a pattern.