Default parameters
Default function parameters allow formal parameters to be initialized with default values if no value or undefined is passed.
function multiply(value1=1, value2=1) {
return value1 * value2;
}
console.log(multiply(4)); // 4
The above default parameter code is equivalent to the following code.
function multiply(value1, value2) {
if (value1 === void 0) { value1 = 1; }
if (value2 === void 0) { value2 = 1; }
return value1 * value2;
}
console.log(multiply(4)); // 4