How to check if an array doesn't contain a string and use it as condition

Question

var name = document.getElementById("namebox").value;

if (array.includes(name) == false) {
   alert(name + " is not in record.")
}

that didn't work and will always return false, how to express the check in other ways? please enlighten, thank you very much

This question is already answered [here](https://stackoverflow.com/questions/1181575/determine-whether-an-array-contains-a-value) — Parag Jadhav, Jun 09 '17 at 04:35
`codepen.io's default engine` what is this a response to? .... again, what browser did that not work in — Jaromanda X, Jun 09 '17 at 04:38
nevermind ... your code (in this question) is fine, your array (students) does not contain what you think it contains ... e,g it contains `student1,score1`,`student2,score2` ... searching for `student1` will fail, as `student1` !== `student1,score1` — Jaromanda X, Jun 09 '17 at 04:44
edited... sorry for the bad question because I am a learning novice... the downvotes are saddening... — Nate, Jun 09 '17 at 04:45
the issue is, that the code you've presented does **not** contain enough of your code to even duplicate the issue - the fault is not with that logic, but with the **data** you are actually working with — Jaromanda X, Jun 09 '17 at 04:46
@JaromandaX oh... thanks... so ".includes" doesn't check the content as string but more like a == comparison?.... — Nate, Jun 09 '17 at 04:48
yes, more like that - you'll want to use `Array.prototype.some` with a callback function that checks `Atring.prototype.indexOf` - perhaps — Jaromanda X, Jun 09 '17 at 04:51

score 3 · Answer 1 · answered Jun 09 '17 at 04:41

3

You may try

if (array.indexOf(name) == -1) {
   alert(name + " is not in record.")
}

answered Jun 09 '17 at 04:41

M. H

Jaromanda X · Accepted Answer · 2017-06-09T05:17:17.320

3

because your array is like

[ "name1,score1", "name2,score2"]

searching for "name1" using includes wont work

you'll want something like

if (!array.some(item => item.split(',')[0] === name)) {
    alert(name + " is not in record.")
}

or in pre ES2015

if (!array.some(function (item) {
    return item.split(',')[0] === name;
})) {
    alert(name + " is not in record.");
}

or if your browser doesn't have Array.prototype.some

if (array.filter(function (item) {
    return item.split(',')[0] === name;
}).length === 0) {
    alert(name + " is not in record.");
}

edited Jun 09 '17 at 05:17

answered Jun 09 '17 at 04:55

Jaromanda X

Read array.prototype.some documentation – Jaromanda X Jun 09 '17 at 05:13
The arrow function odd probably alien to you as well. Right – Jaromanda X Jun 09 '17 at 05:14
I've added some possibly easier to understand code - `item` could be any name, it's just each entry in the array for each iteration of `.some` – Jaromanda X Jun 09 '17 at 05:23
I was guessing... array is the name of the array students[]... and item is the element of the array... students[i][0] ?... and I will have to put them in a loop to check? – Nate Jun 09 '17 at 05:27
dear @Jaromanda X, I failed to understand how to use your methods just by reading documentation (language barrier and intelligence difference may be), but I managed to think of a way that is by constructing a temporary Array and then push all the student[i][0] (names) into it, then only do the checking... other than splitting method you tried to teach me, I also found array flattening methods but I really couldn't understand just by reading... thanks anyhow =) – Nate Jun 09 '17 at 08:08
to be honest, your original design is flawed. Rather than adding "name, score" onto an array, I would be adding an object something like `{student: "name", score: number}` - that way you can find the student using `array.find(item=> item.student === name)` – Jaromanda X Jun 09 '17 at 08:35
I've never used object before and it's the next topic I will start learning =) thanks – Nate Jun 09 '17 at 08:37

2 Answers2