CODEWITHSUNDEEP
javascriptarrays
knot22
knot22

Reputation: 2768

overwriting values in Javascript array does not jive with console output

Here is a simplified version of an array of objects that I'm dealing with in a project -

let test = [];
test['12/1/2019'] = {k1: 25, k2: 'hello'};
test['1/1/2020'] = {k1: 14, k2: 'bonjour'};
console.log(test);
test['12/1/2019'] = {k1: 16, k2: 'ciao'};
test['1/1/2020'] = {k1: 10, k2: 'good day'};

I expected the console output to show this, on account of the console.log(test); being before the lines of code that overwrite the original values:
enter image description here

However, the actual console output is this:
enter image description here

Why is it behaving this way?

Upvotes: 2

Views: 41

Answers (1)

technophyle
technophyle

Reputation: 9149

This is because JavaScript engine runs every code in batches.

From the code, it looks like console.log is called before setting the new values to the array, but in reality, all commands in the current iteration are run first before console.log is run in the next iteration.

And because test is a reference to a memory location for storing values for test array, it now represents the updated value.

The same applies to objects as well.

Upvotes: 2

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