CODEWITHSUNDEEP
javascriptjquery
Brian
Brian

Reputation: 178

jquery .each waiting for function to finish before continuing through loop

I'm essentially trying to loop through a collection of LI tags and insert some text to simulate the look of someone writing a list of things to do. It works, but it writes each of the list items simultaneously instead of waiting. Is there an easy way to achieve this? I have a JS fiddle setup here: http://jsfiddle.net/fZpzT/ but the code looks like this. Thanks.

function addListItems() {
var str = {
    listitem1:'personal background check',
    listitem2:'look into my sketchy neighbor',
    listitem3:'look up my driving record',
    listitem4:'pick up milk',
    listitem5:'wash the car'
}

$('.list-container li').each(function(){
    var z = $(this).attr('id');
    var str2 = str[z];
    var delay = 0;
    for (var i = 0; i <= str2.length; i++) {
        (function(str2){
            delay += 100 + Math.floor(Math.random()*11)*6;
            setTimeout(function(){
                appendStr(str2);       
            },delay);
        })(str2[i])
    }
    function appendStr(str2) {
      $('#'+ z).append(str2);
    }
});
}

Upvotes: 8

Views: 3380

Answers (3)

Ja͢ck
Ja͢ck

Reputation: 173532

I would reverse the workings:

  1. You start with the strings you want to write,

  2. For each string:

    1. Find the corresponding list item (by id)
    2. Write the whole string in typewriter style

    3. Invoke the next iteration when done.

      var strings = [
  'personal background check',
  'look into my sketchy neighbor',
  'look up my driving record',
  'pick up milk',
  'wash the car'
];

function iterate(strings, idx)
{
  if (idx >= strings.length) { return; }

  var id = 'listitem' + (idx + 1),
  el = document.getElementById(id);

  typewriter(el, strings[idx], 0, function() {
    iterate(strings, idx + 1);
  });
}

function typewriter(el, str, idx, cb)
{
  if (idx >= str.length) {
    return cb();
  }

  setTimeout(function() {
    el.innerText = str.substr(0, idx + 1);
    typewriter(el, str, idx + 1, cb);
  }, 100 + Math.floor(Math.random() * 11) * 6);
}

Demo

Upvotes: 3

Snixtor
Snixtor

Reputation: 4297

How about simplifying? Use two variables to iterate the entire contents of a slightly modified data structure in a single loop. Like this. http://jsfiddle.net/cXykd/

var strings = 
[
    { "id":"listitem1", "text": "write the first item" },
    { "id":"listitem2", "text": "write the second item" },
    { "id":"listitem3", "text": "write the third item" },
    { "id":"listitem4", "text": "write the fourth item" },
    { "id":"listitem5", "text": "write the fifth item" },
 ]

var stringsIndex = 0;
var textIndex = 0;

AddString();

function AddString(){
    if (stringsIndex < strings.length){
        if (textIndex >= strings[stringsIndex].text.length)
        {
            stringsIndex++;
            if (stringsIndex == strings.length)
            {
                return;
            }
            textIndex = 0;
        }

        $("#" + strings[stringsIndex].id).append(strings[stringsIndex].text[textIndex]);
        textIndex++;

        var delay = 10 + Math.floor(Math.random()*11)*6;
        setTimeout(AddString, delay);
    }
}

Upvotes: 1

Hari Pachuveetil
Hari Pachuveetil

Reputation: 10374

Make the delay cumulative: Demo on jsFiddle

var str = {
    listitem1: 'write the first item',
    listitem2: 'write the second item',
    listitem3: 'write the third item',
    listitem4: 'write the fourth item',
    listitem5: 'write the fifth item'
}, cumulativeDelay = 0;

$('.list-container li').each(function () {
    var z = $(this).attr('id');
    var str2 = str[z];
    var delay = cumulativeDelay;
    for (var i = 0; i <= str2.length; i++) {
        (function (str2) {
            delay += 100 + Math.floor(Math.random() * 11) * 6;
            setTimeout(function () {
                appendStr(str2);
            }, delay);
        })(str2[i])
    }
    cumulativeDelay = delay;
    function appendStr(str2) {
        $('#' + z).append(str2);
    }
    $(this).css('color', 'red');
});

Upvotes: 4

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