JS passed by copy of a reference

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JS passed by copy of a reference

Creator

Creator

Seonglae Cho

Created

Created

2020 May 7 8:48

Editor

Editor

Seonglae Cho

Edited

Edited

2021 Apr 21 6:46

Refs

Refs

js always call by value

Does Javascript pass by reference?

My 2 Cents.... It's irrelevant whether Javascript passes parameters by reference or value. What really matters is assignment vs mutation. I wrote a longer, more detailed explanation here ( Is JavaScript a pass-by-reference or pass-by-value language?) When you pass anything (Whether that be an object or a primitive), all javascript does is assign a new variable while inside the function...

https://stackoverflow.com/questions/13104494/does-javascript-pass-by-reference

the reference itself is passed by value


function replace(ref) {
    ref = {};           // this code does _not_ affect the object passed
}

function update(ref) {
    ref.key = 'newvalue';  // this code _does_ affect the _contents_ of the object
}

var a = { key: 'value' };
replace(a);  // a still has its original value - it's unmodfied
update(a);   // the _contents_ of 'a' are changed

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