It is called default function parameters . It allows formal parameters to be initialized with default values if no value or undefined is passed. NOTE: It wont ... ... <看更多>

In JavaScript, a parameter has a default value of undefined. It means that if you don't pass the arguments into the function, its parameters will have the ... ... <看更多>

JavaScript Snippet. // Supply default values for parameters // Before, using ES5... function greetES5(message, to) { // Test parameter values in the ... ... <看更多>

js: default value parameters to javascript function - gist:3280052. ... function foo(a, b). {. a = typeof a !== 'undefined' ? a : 42;. b = typeof b !== ... <看更多>

When you don't pass the discount argument into the applyDiscount() function, the function uses a default value which is 0.05 . Similar to JavaScript ... ... <看更多>

someFunction(a, b, x = false) { // a and b are strings, x is true or false ... } In either case, the function can be called without x : ... <看更多>