Can I declare default parameter like
function myFunc( a, b=0)
{
// b is my optional parameter
}
in JavaScript?
Can I declare default parameter like
function myFunc( a, b=0)
{
// b is my optional parameter
}
in JavaScript?
With ES6: This is now part of the language:
function myFunc(a, b = 0) {
// function body
}
Please keep in mind that ES6 checks the values against undefined and not against truthy-ness (so only real undefined values get the default value - falsy values like null will not default).
With ES5:
function myFunc(a,b) {
b = b || 0;
// b will be set either to b or to 0.
}
This works as long as all values you explicitly pass in are truthy.
Values that are not truthy as per MiniGod's comment: null, undefined, 0, false, ''
It's pretty common to see JavaScript libraries to do a bunch of checks on optional inputs before the function actually starts.