How do you access objects within arrays from JSON in JS?

Question

I'm trying to loop through some data that I've passed to my JS script from PHP through AJAX.

The data is:

history: [
["1h", {
    "number": "8651",
    "event": "lock"
}],
["2h", {
    "number": "16456",
    "event": "edit"
}],
["2h", {
    "number": "90",
    "event": "edit"
}],
]

I've parsed the JSON using Jquery with:

var responseData = $.parseJSON(data);
history = JSON.parse(responseData.history);

But every attempt I've made at trying to access this data has thrown an error, or returned meta info about the object.

$.each(history, function (index, value) {
    console.log(value);
});

returns:

function go()

function back()

function forward()

function pushState()

function replaceState()

11

auto

null

How do I access the data?

The reason for parsing twice is that

console.log(typeof responseData.history); // 'string'

Trying:

$.each(responseData.history, function (index, value) {

As per gurvinder372's answer gives the error:

TypeError: cannot use 'in' operator to search for '(b - 1)' in '[["1h",{"number"...'

You're parsing twice.

Jared Smith
– Jared Smith

2018-04-04 15:10:32 +00:00
Commented Apr 4, 2018 at 15:10 — Jared Smith
– Jared Smith, Commented Apr 4, 2018 at 15:10
You cannot parse JSON which was already parsed.

connexo
– connexo

2018-04-04 15:11:02 +00:00
Commented Apr 4, 2018 at 15:11 — connexo
– connexo, Commented Apr 4, 2018 at 15:11

gurvinder372 · Accepted Answer · 2018-04-04 15:15:31Z

3

You cannot edit window.history via assignment, so you are iterating window.history object, iterate responseData.history

$.each(responseData.history, function (index, value) {

Also, as per your code

var responseData = $.parseJSON(data);

responseData is parsed into an object.

edited Apr 4, 2018 at 15:15

answered Apr 4, 2018 at 15:09

gurvinder372

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6 Comments

Jared Smith Over a year ago

Good catch with the implicit global assignment.

gurvinder372 Over a year ago

@JaredSmith That is the only thing that can explain the output OP gets when he iterate history.

connexo Over a year ago

responseData is already a JSON should probably be responseData is already parsed

gurvinder372 Over a year ago

@connexo That is what I had meant, updated nevertheless.

Vintage12 Over a year ago

I tried switching to responseData.history but it seems that it wasn't parsed and is still a string. I've updated the question with the results.

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