function isVariableOrFunction( node ) {
	if ( !node ) {
		return false;
	}
	if ( node.type === 'MemberExpression' ) {
		return !node.computed;
	}
	return (
		node.type === 'Literal' ||
		node.type === 'Identifier' ||
		node.type === 'FunctionExpression'
	);
}
Checks whether a node is a variable or function expression.

@private
@param {ASTNode} node - node to examine
@returns {boolean} boolean indicating whether node represents a variable or function expression