Develop Reference

Not able to add list items to HTML Document

I am using fetch() command to get an array of data in JSON format. I am using function fetchURL() to get data in JSON format. I use async-await. Then in each data received I am trying to add it's login field to an ordered list that I have created in the HTML file.
I have made a createListItem() function to find the ordered list tag in the HTML file and append in it the login field. But first I try to store all the login fields in an array arr. But I am not able to store the login fields in it.
But when I directly use createListItem() function to create a list item with login" field as text I am able to add these fields to the ordered list and hence I get the ordered list.
I am commenting out the lines that get me direct Output on the browser window when I do not store the login fields in the arr:
Code:
function createListItem(text) {
const parent = document.getElementsByTagName("ol");
const entry = document.createElement("li");
entry.textContent = text;
parent[0].appendChild(entry);
}
const url = "https://api.github.com/users ";
async function fetchURL() {
return (await fetch(url)).json();
}
let arr = [];
async function createList() {
const data = await fetchURL();
for (let i = 0; i < data.length; i++) {
//createListItem(`${data[i].login}`);
arr.push(data[i].login);
}
}
createList();

you are getting the data in array, you need to create list after you call createList() function:
createList().then(function(){
arr.forEach(element => {
createListItem(element);
});
});
you can also define arr in the createList function and return that then your code would be like this:
async function createList() {
let arr = [];
const data = await fetchURL();
for (let i = 0; i < data.length; i++) {
//createListItem(`${data[i].login}`);
arr.push(data[i].login);
}
return arr;
}
createList().then(arr=>{
arr.forEach(element => {
createListItem(element);
});
});

You can achieve your objective with just one async function:
const url="http://jsonplaceholder.typicode.com/users";
async function getList(u){
const arr=(await fetch(u).then(r=>r.json())).map(e=>e.username);
document.querySelector("ol").innerHTML=arr.map(u=>`<li>${u}</li>`).join("");
console.log(arr);
}
getList(url);
<h2>List of login names</h2>
<ol></ol>
<p>end of page</p>
In the above snippet I used the public resource provided by typicode.com and extracted the property of username instead of login.

Codestructure in async javascript

I have a simple program that reads a css file (which is available on GitHub pages) and parse the css to an array so I can put at in a list.
I have an dictionary with words, like a vocabulary list which shows me the translation and I can also search for words.
Everything works fine so far but I am really new and this is my first project and I want some advise about my codestructure.
At the moment I have to fetch the csv file (which never changes) in different methods with getData. I do this in init dictionary and again in search and show, because I need the dictionary again. Wouldn’t it be better to get the data once and then use it with all functions?
But then I have to write a lot function into another which is not so good practice I think.
I would really appreciate some advise or link or topics/ direction I have to research, because I can’t find an answer about how to structure this well.
I just use html, css and js without any framework or library.
initDictionary();
async function initDictionary(){
//get data
const dictionary = await getData();
//fill html list with words
fillList(dictionary);
}
//show translation and info when click on word
show = async function (i){
let dictionary = await getData();
document.getElementById("word-text").innerHTML = dictionary[i].Wort;
document.getElementById("info").innerHTML = dictionary[i].Notizen;
}
//search stuff
search = async function() {
let dictionary = await getData();
let query = document.getElementById('search').value;
console.log(query);
if (query == ""){
return;
}
//init found to false
let found = -1;
for(let i=0; i< dictionary.length; i++){
if(query == dictionary[i].Übersetzung){
found = i;
break;
}else {
document.getElementById("word-text").innerHTML = "word not found";
document.getElementById("info").innerHTML ="";
}
}
if ( found >= 0){
show (found);
query = document.getElementById('search').value="";
}
}
//Start search when u press enter
let input = document.getElementById("search");
input.addEventListener("keyup", function(event) {
console.log(event);
if (event.key=== "Enter") {
search();
}
});
// get data
async function getData(){
const csv = await fetch('https://aboutwhite.github.io/data/data.csv');
let scvText = await csv.text();
let dictionary = csvToArray(scvText);
return dictionary;
}
// fill html list with words
function fillList(dictionary){
for(let i=0; i< dictionary.length; i++){
document.getElementById('word-list').innerHTML += "<li onclick='show("+i+")'>" + dictionary[i].Übersetzung+"</li>";
}
}
//parse csv to array
function csvToArray(str){
let delimiter = ","
const headers = str.slice(0, str.indexOf("\n")).split(delimiter);
const rows = str.slice(str.indexOf("\n") + 1).split("\n");
const arr = rows.map(function (row) {
const values = row.split(delimiter);
const el = headers.reduce(function (object, header, index) {
object[header] = values[index];
return object;
}, {});
return el;
});
return arr;
}

How to make react stop duplicating elements on click

The problem is that every time I click on an element with a state things appear twice. For example if i click on a button and the result of clicking would be to output something in the console, it would output 2 times. However in this case, whenever I click a function is executed twice.
The code:
const getfiles = async () => {
let a = await documentSpecifics;
for(let i = 0; i < a.length; i++) {
var wrt = document.querySelectorAll("#writeto");
var fd = document.querySelector('.filtered-docs');
var newResultEl = document.createElement('div');
var writeToEl = document.createElement('p');
newResultEl.classList.add("result");
writeToEl.id = "writeto";
newResultEl.appendChild(writeToEl);
fd.appendChild(newResultEl);
listOfNodes.push(writeToEl);
listOfContainers.push(newResultEl);
wrt[i].textContent = a[i].data.documentName;
}
}
The code here is supposed to create a new div element with a paragraph tag and getting data from firebase firestore, will write to the p tag the data. Now if there are for example 9 documents in firestore and i click a button then 9 more divs will be replicated. Now in total there are 18 divs and only 9 containing actual data while the rest are just blank. It continues to create 9 more divs every click.
I'm also aware of React.Strictmode doing this for some debugging but I made sure to take it out and still got the same results.
Firebase code:
//put data in firebase
createFileToDb = () => {
var docName = document.getElementById("title-custom").value; //get values
var specifiedWidth = document.getElementById("doc-width").value;
var specifiedHeight = document.getElementById("doc-height").value;
var colorType = document.getElementById("select-color").value;
parseInt(specifiedWidth); //transform strings to integers
parseInt(specifiedHeight);
firebase.firestore().collection("documents")
.doc(firebase.auth().currentUser.uid)
.collection("userDocs")
.add({
documentName: docName,
width: Number(specifiedWidth), //firebase-firestore method for converting the type of value in the firestore databse
height: Number(specifiedHeight),
docColorType: colorType,
creation: firebase.firestore.FieldValue.serverTimestamp() // it is possible that this is necessary in order to use "orderBy" when getting data
}).then(() => {
console.log("file in database");
}).catch(() => {
console.log("failed");
})
}
//get data
GetData = () => {
return firebase.firestore()
.collection("documents")
.doc(firebase.auth().currentUser.uid)
.collection("userDocs")
.orderBy("creation", "asc")
.get()
.then((doc) => {
let custom = doc.docs.map((document) => {
var data = document.data();
var id = document.id;
return { id, data }
})
return custom;
}).catch((err) => {console.error(err)});
}
waitForData = async () => {
let result = await this.GetData();
return result;
}
//in render
let documentSpecifics = this.waitForData().then((response) => response)
.then((u) => {
if(u.length > 0) {
for(let i = 0; i < u.length; i++) {
try {
//
} catch(error) {
console.log(error);
}
}
}
return u;
});
Edit: firebase auth is functioning fine so i dont think it has anything to do with the problem
Edit: This is all in a class component
Edit: Clicking a button calls the function createFileToDb

I think that i found the answer to my problem.
Basically, since this is a class component I took things out of the render and put some console.log statements to see what was happening. what i noticed is that it logs twice in render but not outside of it. So i took the functions out.
Here is the code that seems to fix my issue:
contain = () => {
const documentSpecifics = this.waitForData().then((response) => {
var wrt = document.getElementsByClassName('writeto');
for(let i = 0; i < response.length; i++) {
this.setNewFile();
wrt[i].textContent = response[i].data.documentName;
}
return response;
})
this.setState({
docs: documentSpecifics,
docDisplayType: !this.state.docDisplayType
})
}
As for creating elements i put them in a function so i coud reuse it:
setNewFile = () => {
const wrt = document.querySelector(".writeto");
const fd = document.querySelector("#filtered-docs");
var newResultEl = document.createElement('div');
newResultEl.classList.add("result");
var wrtEl = document.createElement('p');
wrtEl.classList.add("writeto");
fd.appendChild(newResultEl);
newResultEl.appendChild(wrtEl);
}
The firebase and firestore code remains the same.
the functions are called through elements in the return using onClick.

can't get data form array

I try to get data from the array but I get undefined
please check the image of my problem
I don't know what I'm missing
please help
I have an array called nameTable of string
when I console.log(this.nameTable) I got this : check the image please
enter image description here
and when I click to arrow I got this : check image please
enter image description here
the problem is the table has 5 element I want to show them so I make for loop to do that
for (let i = 0; i < 5; i++){
console.log(this.nameTable[i])
}
but us you can see in the image I got undefined
enter image description here
here the code :
employeeL:Array<Awinjard> = [];
inv_agentTab: Array<Inv_agent> = [];
drafbiesTab: Array<Drafbies> = [];
nameemployee: string = "";
inv_agentNombre: number = 0;
matriculeTable: Array<number> = [];
nameTable:Array<string> = [];
validatationTable: Array<number> = [];
ngOnInit() {
this.folder = this.activatedRoute.snapshot.paramMap.get('id');
this.awinjard.getAwinjardMatricule().subscribe(res => {
this.inv_agentTab = res as Array<Inv_agent>
this.inv_agentTab.forEach(element => {
this.matriculeTable[this.inv_agentNombre] = element.AGENT;
this.validatationTable[this.inv_agentNombre] = element.VLD;
this.inv_agentNombre++;
this.awinjard.getAwinjardNameAr().subscribe(res2 => {
this.drafbiesTab = res2 as Array<Drafbies>
this.drafbiesTab=this.drafbiesTab.filter((employee)=>employee.DECAFFE==element.AGENT)
this.nameemployee = this.drafbiesTab[0].AR_DELAFFE;
this.nameTable.push(this.nameemployee);
})
});
for (let i = 0; i < 5; i++){
// here the problem I can't get the data form nameTable array
console.log(this.nameTable[i])
let awin= <Awinjard> {
matricule: this.matriculeTable[i],
fullname: this.nameTable[i],
status: true,
done: 1,
mustBeDone:40
}
this.employeeL.push(awin);
}
})
}

You have subscribed to getAwinjardNameAr and before that response, you are trying to access the nameTable array, which is why you get undefined. #raishav-hanspal's solution is right to solve your issue, but a code change can keep things straightforward. I suggest you to write that code inside your for loop inside your subscribe. Here's the alteration:
this.awinjard.getAwinjardNameAr().subscribe(res2 => {
this.drafbiesTab = res2 as Array<Drafbies>
this.drafbiesTab=this.drafbiesTab.filter((employee)=>employee.DECAFFE==element.AGENT)
this.nameemployee = this.drafbiesTab[0].AR_DELAFFE;
this.nameTable.push(this.nameemployee);
let awin= <Awinjard> {
matricule: this.matriculeTable[this.inv_agentNombre],
fullname: this.nameemployee,
status: true,
done: 1,
mustBeDone:40
}
this.employeeL.push(awin);
})

You can move the code where you're logging nameTable[] inside the subscribe (where you are pushing the values into nameTable[]).
A complete solution is to use complete in subscribe() -->
this.awinjard.getAwinjardNameAr().subscribe(res2 => {
this.drafbiesTab = res2 as Array<Drafbies>
this.drafbiesTab=this.drafbiesTab.filter((employee)=>employee.DECAFFE==element.AGENT)
this.nameemployee = this.drafbiesTab[0].AR_DELAFFE;
this.nameTable.push(this.nameemployee);
},err => {console.log(err)}, ()=> {
for (let i = 0; i < 5; i++){
// here the problem I can't get the data form nameTable array
console.log(this.nameTable[i])}})
});
You can read more on https://angular.io/guide/observables

How to fetch and display a specific index in a JSON file using a Javascript loop

I am currently using fetch in javascript to obtain information from another site into my own. The issue I am having is, I am using a loop to display all of the indexes of the JSON file into my site. I actually want to get specific indexes to show, not all of them, for example, index 2,4 and 6.
Here is my code so far:
window.addEventListener("load", (event)=>{
const requestURL = 'https://byui-cit230.github.io/weather/data/towndata.json';
fetch(requestURL)
.then(function (response) {
return response.json();
})
.then(function (jsonObject) {
const towns = jsonObject['towns'];
for (let i = 0; i < towns.length; i++ ) {
let towninfo = document.createElement('section');
let townname = document.createElement('h2');
townname.textContent = towns[i].name;
towninfo.appendChild(townname);
document.querySelector('div.weathertowns').appendChild(towninfo);
}
});
})
This displays all of the towns in reference, but I only want to display the title of 3 specific ones. Any suggestions on how to proceed with this?

something like that
window.addEventListener("load", (event)=>
{
const requestURL = 'https://byui-cit230.github.io/weather/data/towndata.json'
, divWeathertowns = document.querySelector('div.weathertowns')
;
fetch(requestURL)
.then( response=>response.json() )
.then( jsonObject=>
{
const towns = jsonObject['towns']
;
for ( let i of [2,4,6] )
{
let towninfo = document.createElement('section')
, townname = document.createElement('h2')
;
townname.textContent = towns[i].name;
towninfo.appendChild(townname);
divWeathertowns.appendChild(towninfo);
}
});
})
<div class="weathertowns"></div>