Here are 2 functions in the simplest form. I'm working with jquery.
What is the best way to pass var str from the first function to the second one?
function a() {
var str = "first";
};
function b() {
var new = str + " second";
};
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3 Answers
You need to either pass it between them, or it seems from your example, just declare it in a higher scope:
var str;
function a(){
str="first";
}
function b(){
var something = str +" second"; //new is reserved, use another variable name
}
9 Comments
Jacob Relkin
@Nick I like passing them around better than leaving them out in the open for others to modify.
Nick Craver
@Jacob - You're assuming
a has anything to do with b though, it could just be a() in one place, possibly never even called, then b() in another.
Phrogz
Man, it's really hard to decide which one of these answers to go with. Both are very, very valid given various uses, and there's no way to tell given the sparse details from the OP.
david
The module pattern allows you to do this while still keeping the 'str' variable protected from outside editing. Quick example of a shared var: jsfiddle.net/Ma8Hs
David Tang
@Jacob, from this very limited example it's hard to see the OP's intended use of the variable. Choosing whether to pass as an argument, or declaring at a high scope, or even
b.call(new String(str)) for arguments sake, really depends on the situation... |
Use function parameters, like this:
function a() {
var str = "first";
b(str);
}
function b(s) {
var concat = s + " second";
//do something with concat here...
}
You could just declare a variable higher up in the scope chain, but I opt to use arguments to restrict variable access to only the contexts that absolutely need it.
Oh yeah, isn't that called the principle of least privilege?
Comments
i use..
function a(){
let str = "first";
localStorage.setItem('value1', `${str}`);}
function b(){
let str = localStorage.getItem('value1');
let new = str + " second";}