How can I generate booking code in the vue? - javascript

I try like this :
methods: {
generateCode () {
const letters = '1217CHELS323412eafoo'
const uniqueId = function () {
let text = ''
for (let i = 0; i < 6; i++) {
text += letters.charAt(Math.floor(Math.random() * letters.length))
}
return text
}
return uniqueId()
}
}
Some examples of the results: : L1LE3C, o23H1f, HeLe34
Is this code perfect? I mean every time this method is called, it will definitely generate a unique booking code

You have very few choice of letter, and you only generate 6 characters code, I made a simple script to check how many times do you have to generate the code until it matches with LS73ea
12787899 times
20141743 times
31479934 times
18819863 times
30361586 times
5533616 times
6495725 times
13431128 times
29765633 times
18367311 times
That's a quite high chances of duplicates.
I don't understand why would you include same characters in the letters. Instead, do something like this:
methods: {
generateCode () {
// Alphanumeric
const characters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'
const uniqueId = function () {
let text = ''
for (let i = 0; i < 8; i++) {
text += characters.charAt(Math.floor(Math.random() * characters.length))
}
return text
}
return uniqueId()
}
}
That function will generate a code like HrsK9wgF, and have way less chance of duplicates, and if you want to make it even lower, you can also:
Add more characters like symbol (-, _) to the choice of letters
Increase the generated code length
As for reference, Youtube's video id used A-Z, a-z, 0-9, - and _ for the choice of characters, and has 11 characters length.
Apart from that, are you sure you want to generate the ID on the front end app? It seems like it should be generated on your backend app instead.

Related

Javascript: Handling timers with multiple lengths of delay?

Essentially what I'm trying to get this to do is display a list of words given by #words on a textarea #display.
Each word is displayed one at a time, delayed by an amount of time designated by getTextSpeed which retrieves speed options chosen by the user.
For example, if the user selects 350 WPM as their desired speed for delay, then each word will have a delay of 117 ms. If they decide to change it to 400 WPM, the delay should decrease in real time dynamically to a delay of 150 ms without having to restart the display animation.
Additionally, if the word contains a character of punctuation, then the delay after the word is displayed should be doubled (ex: 117 ms to 234 ms) and the character should be removed. If there's multiple characters of punctuation, just one should be removed (ex: "..." --> "..")
Below are the relevant methods and my attempt at implementing this behavior.
If you need the rest of the code (for testing purposes?), please see these pastebin links: HTML, Javascript, CSS.
I haven't encountered any errors in the console, but the actual reflected behavior isn't what I want for sure.
There's a lag period at the beginning of starting the animation, which seems to vary based on the length of the input text, and the delay between each word is far, far longer than it should be. Additionally, the punctuation doesn't appear to remove correctly. EDIT #1: I just double-checked the string.remove syntax and you're supposed to put the actual String, not actually call the method from the String superclass.
Please let me know if you need any other information.
var timer;
function start() {
var text = document.getElementById("words").value;
var list = text.split(/\s+/);
runDisplay(list, "display");
}
function runDisplay(data, id) {
var reader = document.getElementById(id);
var index = 0;
var punctDelay = 0;
if (timer) {
clearInterval(timer);
}
if (data.length) {
timer = setInterval(function() {
var punctuation = [".", ",", ":", ";", "!", "?"];
var word = data[index++];
for (var j = 0; j < punctuation.length; j++) {
if (!(word.indexOf(punctuation[j]) === -1)) {
// word = String.replace(punctuation[j], '');
word = word.replace(punctuation[j], ''); // see edit #1
punctDelay = getTextSpeed();
}
}
reader.innerHTML = word;
index = index % data.length;
}, getTextSpeed() + punctDelay); // change speed dynamically in real time
}
}
function stop() {
var display = document.getElementById("display");
clearInterval(timer);
timer = null;
display.innerHTML = "";
}
function getTextSpeed() {
var speeds = document.getElementById("speed");
return speeds.options[speed.selectedIndex].value;
}

Javascript array length through user input

I have a problem in Javascript I want to make a form which have one input text field and one button when I click on the button window.prompt is called.
It will prompt depend upon my array length but I want array length get through input text field when I write 10 it will prompt 10 times when I write 2 it will prompt 2 times.
How can i write this type of query?
I tried this code but its not working.
words = new Array (4);
function a() {
for ( k = 0 ; k < words.length ; k = k + 1 ) {
words[ k ] = window.prompt( "Enter word # " + k, "" ) ;
}
}
Maybe you forgot to call your function a().
Some remarks about your code:
You don't have to specify an initial array size, e.g. words = [] or words = new Array() is enough.
Also k=k+1 is usually written as k++.
A remark about asking questions:
Use punctuation to make sentences! Your whole question is one sentence.
Hopefully it's just the snippet of code but I hope you are using var somewhere to declare all those variables.
Otherwise this should do the trick, however not sure what you are trying to achieve but this sounds like a bad user experience.
Here is the jsffidle http://jsfiddle.net/R2bCz/1/
function Handler(event) {
var count = event.target.value;
var i = 0;
var words = [];
var word;
for (; i < count; i++) {
word = window.prompt("Enter word # " + i, "");
words.push(word);
}
}
$("#multi").on("change", Handler);

Javascript for Variations with Repetition (combinatorics) of missing string characters

My question is similar to THIS question that hasn't been answered yet.
How can I make my code (or any javascript code that might be suggested?) find all possible solutions of a known string length with multiple missing characters in variation with repetition?
I'm trying to take a string of known character lengths and find missing characters from that string. For example:
var missing_string = "ov!rf!ow"; //where "!" are the missing characters
I'm hoping to run a script with a specific array such as:
var r = new Array("A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V",
"W","X","Y","Z",0,1,2,3,4,5,6,7,8,9);
To find all the possible variations with repetition of those missing characters to get a result of:
ovArfAow
ovBrfAow
ovCrfAow
...
ovBrfBow
ovBrfCow
...
etc //ignore the case insensitive, just to emphasize the example
and of course, eventually find ovErfLow within all the variations with repetition.
I've been able to make it work with 1 (single) missing character. However, when I put 2 missing characters with my code it obviously repeats the same array character for both missing characters which is GREAT for repition but I also need to find without repetition as well and might need to have 3-4 missing characters as well which may or may not be repeated. Here's what I have so far:
var r = new Array("A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V",
"W","X","Y","Z",0,1,2,3,4,5,6,7,8,9);
var missing_string = "he!!ow!r!d";
var bt_lng = missing_string.length;
var bruted="";
for (z=0; z<r.length; z++) {
for(var x=0;x<bt_lng;x++){
for(var y=0;y<r.length;y++){
if(missing_string.charAt(x) == "!"){
bruted += r[z];
break;
}
else if(missing_string.charAt(x) == r[y]){
bruted += r[y];
}
}
}
console.log("br: " + bruted);
bruted="";
}
This works GREAT with just ONE "!":
helloworAd
helloworBd
helloworCd
...
helloworLd
However with 2 or more "!", I get:
heAAowArAd
heBBowBrBd
heCCowCrCd
...
heLLowLrLd
which is good for the repetition part but I also need to test all possible array M characters in each missing character spot.
Maybe the following function in pure javascript is a possible solution for you. It uses Array.prototype.reduce to create the cartesian product c of the given alphabet x, whereby its power n depends on the count of the exclamation marks in your word w.
function combinations(w) {
var x = new Array(
"A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V",
"W","X","Y","Z",0,1,2,3,4,5,6,7,8,9
),
n = w.match(/\!/g).length,
x_n = new Array(),
r = new Array(),
c = null;
for (var i = n; i > 0; i--) {
x_n.push(x);
}
c = x_n.reduce(function(a, b) {
var c = [];
a.forEach(function(a) {
b.forEach(function(b) {
c.push(a.concat([b]));
});
});
return c;
}, [[]]);
for (var i = 0, j = 0; i < c.length; i++, j = 0) {
r.push(w.replace(/\!/g, function(s, k) {
return c[i][j++];
}));
}
return r;
}
Call it like this console.log(combinations("ov!rf!ow")) in your browser console.

Finding keywords in texts

I have an array with incidents that has happened, that are written in free text and therefore aren't following a pattern except for some keywords, eg. "robbery", "murderer", "housebreaking", "car accident" etc. Those keywords can be anywhere in the text, and I want to find those keywords and add those to categories, eg. "Robberies".
In the end, when I have checked all the incidents I want to have a list of categories like this:
Robberies: 14
Murder attempts: 2
Car accidents: 5
...
The array elements can look like this:
incidents[0] = "There was a robbery on Amest Ave last night...";
incidents[1] = "There has been a report of a murder attempt...";
incidents[2] = "Last night there was a housebreaking in...";
...
I guess the best here is to use regular expressions to find the keywords in the texts, but I really suck at regexp and therefore need some help here.
The regular expressions is not correct below, but I guess this structure would work?
Is there a better way of doing this to avoid DRY?
var trafficAccidents = 0,
robberies = 0,
...
function FindIncident(incident) {
if (incident.match(/car accident/g)) {
trafficAccidents += 1;
}
else if (incident.match(/robbery/g)) {
robberies += 1;
}
...
}
Thanks a lot in advance!
The following code shows an approach you can take. You can test it here
var INCIDENT_MATCHES = {
trafficAccidents: /(traffic|car) accident(?:s){0,1}/ig,
robberies: /robbery|robberies/ig,
murder: /murder(?:s){0,1}/ig
};
function FindIncidents(incidentReports) {
var incidentCounts = {};
var incidentTypes = Object.keys(INCIDENT_MATCHES);
incidentReports.forEach(function(incident) {
incidentTypes.forEach(function(type) {
if(typeof incidentCounts[type] === 'undefined') {
incidentCounts[type] = 0;
}
var matchFound = incident.match(INCIDENT_MATCHES[type]);
if(matchFound){
incidentCounts[type] += matchFound.length;
};
});
});
return incidentCounts;
}
Regular expressions make sense, since you'll have a number of strings that meet your 'match' criteria, even if you only consider the differences in plural and singular forms of 'robbery'. You also want to ensure that your matching is case-insensitive.
You need to use the 'global' modifier on your regexes so that you match strings like "Murder, Murder, murder" and increment your count by 3 instead of just 1.
This allows you to keep the relationship between your match criteria and incident counters together. It also avoids the need for global counters (granted INCIDENT_MATCHES is a global variable here, but you can readily put that elsewhere and take it out of the global scope.
Actually, I would kind of disagree with you here . . . I think string functions like indexOf will work perfectly fine.
I would use JavaScript's indexOf method which takes 2 inputs:
string.indexOf(value,startPos);
So one thing you can do is define a simple temporary variable as your cursor as such . . .
function FindIncident(phrase, word) {
var cursor = 0;
var wordCount = 0;
while(phrase.indexOf(word,cursor) > -1){
cursor = incident.indexOf(word,cursor);
++wordCount;
}
return wordCount;
}
I have not tested the code but hopefully you get the idea . . .
Be particularly careful of the starting position if you do use it.
RegEx makes my head hurt too. ;) If you're looking for exact matches and aren't worried about typos and misspellings, I'd search the incident strings for substrings containing the keywords you're looking for.
incident = incident.toLowerCase();
if incident.search("car accident") > 0 {
trafficAccidents += 1;
}
else if incident.search("robbery") > 0 {
robberies += 1;
}
...
Use an array of objects to store all the many different categories you're searching for, complete with an appropiate regular expression and a count member, and you can write the whole thing in four lines.
var categories = [
{
regexp: /\brobbery\b/i
, display: "Robberies"
, count: 0
}
, {
regexp: /\bcar accidents?\b/i
, display: "Car Accidents"
, count: 0
}
, {
regexp: /\bmurder\b/i
, display: "Murders"
, count: 0
}
];
var incidents = [
"There was a robbery on Amest Ave last night..."
, "There has been a report of an murder attempt..."
, "Last night there was a housebreaking in..."
];
for(var x = 0; x<incidents.length; x++)
for(var y = 0; y<categories.length; y++)
if (incidents[x].match(categories[y].regexp))
categories[y].count++;
Now, no matter what you need, you can simply edit one section of code, and it will propagate through your code.
This code has the potential to categorize each incident in multiple categories. To prevent that, just add a 'break' statement to the if block.
You could do something like this which will grab all words found on each item in the array and it will return an object with the count:
var words = ['robbery', 'murderer', 'housebreaking', 'car accident'];
function getAllIncidents( incidents ) {
var re = new RegExp('('+ words.join('|') +')', 'i')
, result = {};
incidents.forEach(function( txt ) {
var match = ( re.exec( txt ) || [,0] )[1];
match && (result[ match ] = ++result[ match ] || 1);
});
return result;
}
console.log( getAllIncidents( incidents ) );
//^= { housebreaking: 1, car accident: 2, robbery: 1, murderer: 2 }
This is more a a quick prototype but it could be improved with plurals and multiple keywords.
Demo: http://jsbin.com/idesoc/1/edit
Use an object to store your data.
events = [
{ exp : /\brobbery|robberies\b/i,
// \b word boundary
// robbery singular
// | or
// robberies plural
// \b word boundary
// /i case insensitive
name : "robbery",
count: 0
},
// other objects here
]
var i = events.length;
while( i-- ) {
var j = incidents.length;
while( j-- ) {
// only checks a particular event exists in incident rather than no. of occurrences
if( events[i].exp.test( incidents[j] ) {
events[i].count++;
}
}
}
Yes, that's one way to do it, although matching plain-words with regex is a bit of overkill — in which case, you should be using indexOf as rbtLong suggested.
You can further sophisticate it by:
appending the i flag (match lowercase and uppercase characters).
adding possible word variations to your expression. robbery could be translated into robber(y|ies), thus matching both singular and plural variations of the word. car accident could be (car|truck|vehicle|traffic) accident.
Word boundaries \b
Don't use this. It'll require having non-alphanumeric characters surrounding your matching word and will prevent matching typos. You should make your queries as abrangent as possible.
if (incident.match(/(car|truck|vehicle|traffic) accident/i)) {
trafficAccidents += 1;
}
else if (incident.match(/robber(y|ies)/i)) {
robberies += 1;
}
Notice how I discarded the g flag; it stands for "global match" and makes the parser continue searching the string after the first match. This seems unnecessary as just one confirmed occurrence is enough for your needs.
This website offers an excellent introduction to regular expressions
http://www.regular-expressions.info/tutorial.html

generate random string for div id

I want to display YouTube videos on my website, but I need to be able to add a unique id for each video that's going to be shared by users. So I put this together, and I have run into a little problem. I am trying to get the JavaScript to add a random string for the div id, but it's not working, showing the string:
<script type='text/javascript' src='jwplayer.js'></script>
<script type='text/javascript'>
function randomString(length) {
var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz'.split('');
if (! length) {
length = Math.floor(Math.random() * chars.length);
}
var str = '';
for (var i = 0; i < length; i++) {
str += chars[Math.floor(Math.random() * chars.length)];
}
return str;
}
var div = randomString(8);
</script>
<div id='div()'>This text will be replaced</div>
<script type='text/javascript'>
jwplayer('div()').setup({
'flashplayer': 'player.swf',
'file': 'http://www.youtube.com/watch?v=4AX0bi9GXXY',
'controlbar': 'bottom',
'width': '470',
'height': '320'
});
</script>
I really like this function:
function guidGenerator() {
var S4 = function() {
return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
};
return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());
}
From Create GUID / UUID in JavaScript?
2018 edit: I think this answer has some interesting info, but for any practical applications you should use Joe's answer instead.
A simple way to create a unique ID in JavaScript is to use the Date object:
var uniqid = Date.now();
That gives you the total milliseconds elapsed since January 1st 1970, which is a unique value every time you call that.
The problem with that value now is that you cannot use it as an element's ID, since in HTML, IDs need to start with an alphabetical character. There is also the problem that two users doing an action at the exact same time might result in the same ID. We could lessen the probability of that, and fix our alphabetical character problem, by appending a random letter before the numerical part of the ID.
var randLetter = String.fromCharCode(65 + Math.floor(Math.random() * 26));
var uniqid = randLetter + Date.now();
This still has a chance, however slim, of colliding though. Your best bet for a unique id is to keep a running count, increment it every time, and do all that in a single place, ie, on the server.
Here is the reusable function to generate the random IDs :
function revisedRandId() {
return Math.random().toString(36).replace(/[^a-z]+/g, '').substr(2, 10);
}
// It will not start with the any number digit so it will be supported by CSS3
I think some folks here haven't really focused on your particular question. It looks like the problem you have is in putting the random number in the page and hooking the player up to it. There are a number of ways to do that. The simplest is with a small change to your existing code like this to document.write() the result into the page. I wouldn't normally recommend document.write(), but since your code is already inline and what you were trying do already was to put the div inline, this is the simplest way to do that. At the point where you have the random number, you just use this to put it and the div into the page:
var randomId = "x" + randomString(8);
document.write('<div id="' + randomId + '">This text will be replaced</div>');
and then, you refer to that in the jwplayer set up code like this:
jwplayer(randomId).setup({
And the whole block of code would look like this:
<script type='text/javascript' src='jwplayer.js'></script>
<script type='text/javascript'>
function randomString(length) {
var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghiklmnopqrstuvwxyz'.split('');
if (! length) {
length = Math.floor(Math.random() * chars.length);
}
var str = '';
for (var i = 0; i < length; i++) {
str += chars[Math.floor(Math.random() * chars.length)];
}
return str;
}
var randomId = "x" + randomString(8);
document.write('<div id="' + randomId + '">This text will be replaced</div>');
jwplayer(randomId).setup({
'flashplayer': 'player.swf',
'file': 'http://www.youtube.com/watch?v=4AX0bi9GXXY',
'controlbar': 'bottom',
'width': '470',
'height': '320'
});
</script>
Another way to do it
I might add here at the end that generating a truly random number just to create a unique div ID is way overkill. You don't need a random number. You just need an ID that won't otherwise exist in the page. Frameworks like YUI have such a function and all they do is have a global variable that gets incremented each time the function is called and then combine that with a unique base string. It can look something like this:
var generateID = (function() {
var globalIdCounter = 0;
return function(baseStr) {
return(baseStr + globalIdCounter++);
}
})();
And, then in practical use, you would do something like this:
var randomId = generateID("myMovieContainer"); // "myMovieContainer1"
document.write('<div id="' + randomId + '">This text will be replaced</div>');
jwplayer(randomId).setup({
i like this simple one:
function randstr(prefix)
{
return Math.random().toString(36).replace('0.',prefix || '');
}
since id should (though not must) start with a letter, i'd use it like this:
let div_id = randstr('youtube_div_');
some example values:
youtube_div_4vvbgs01076
youtube_div_1rofi36hslx
youtube_div_i62wtpptnpo
youtube_div_rl4fc05xahs
youtube_div_jb9bu85go7
youtube_div_etmk8u7a3r9
youtube_div_7jrzty7x4ft
youtube_div_f41t3hxrxy
youtube_div_8822fmp5sc8
youtube_div_bv3a3flv425
I also needed a random id, I went with using base64 encoding:
btoa(Math.random()).substring(0,12)
Pick however many characters you want, the result is usually at least 24 characters.
Based on HTML 4, the id should start from letter:
ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
So, one of the solutions could be (alphanumeric):
var length = 9;
var prefix = 'my-awesome-prefix-'; // To be 100% sure id starts with letter
// Convert it to base 36 (numbers + letters), and grab the first 9 characters
// after the decimal.
var id = prefix + Math.random().toString(36).substr(2, length);
Another solution - generate string with letters only:
var length = 9;
var id = Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, length);
Or you could use Cripto since it's already built in(except in IE11, I swear these guys havent updated in years!)
https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues#Examples
var id = new Uint32Array(10);
window.crypto.getRandomValues(id);
I also found this:
https://gist.github.com/6174/6062387#gistcomment-3255605
let length = 32;
let id = crypto.randomBytes(length).toString("base64");
There's a lot of ways to do this, but for most people, there's no reason to reinvent the wheel :)
A edited version of #jfriend000 version:
/**
* Generates a random string
*
* #param int length_
* #return string
*/
function randomString(length_) {
var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghiklmnopqrstuvwxyz'.split('');
if (typeof length_ !== "number") {
length_ = Math.floor(Math.random() * chars.length_);
}
var str = '';
for (var i = 0; i < length_; i++) {
str += chars[Math.floor(Math.random() * chars.length)];
}
return str;
}
For generating random ids, you can also use the standard crypto API with its randomUUID() function which is available in node.js (>=v16.7.0) and all relevant browsers except Safari:
const uuid = crypto.randomUUID()
console.log(uuid)
// prints e.g. "7f3f4512-fcf9-45fe-b726-512bba403426"
I would suggest that you start with some sort of placeholder, you may have this already, but its somewhere to append the div.
<div id="placeholder"></div>
Now, the idea is to dynamically create a new div, with your random id:
var rndId = randomString(8);
var div = document.createElement('div');
div.id = rndId
div.innerHTML = "Whatever you want the content of your div to be";
this can be apended to your placeholder as follows:
document.getElementById('placeholder').appendChild(div);
You can then use that in your jwplayer code:
jwplayer(rndId).setup(...);
Live example: http://jsfiddle.net/pNYZp/
Sidenote: Im pretty sure id's must start with an alpha character (ie, no numbers) - you might want to change your implementation of randomstring to enforce this rule. (ref)
May I an share an intuitive way to generate a randomID ?
const getRandomID = (length: number) => {
let text = '';
const possible = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
for (let i = 0; i < length; i++) {
text += possible.charAt(Math.floor(Math.random() * possible.length));
}
return text;
}
Here is an easy one liner:
const generateUniqueID = (idLength) => [...Array(idLength).keys()].map((elem)=>Math.random().toString(36).substr(2, 1)).join("")
Where all you do is enter the idLength and it will return a unique id of that length.
generateUniqueID(23)
>>>'s3y9uebzuo73ih79g0s9p2q' // Id of length 23
First. Assign an id to your div. Like this:
<div id="uniqueid">This text will be replaced</div>
After that, add inside your <script> tag following code:
Document.getElementById("uniqueid").id = randomString(8);
window.btoa(String.fromCharCode(...window.crypto.getRandomValues(new Uint8Array(5))))
Using characters except ASCII letters, digits, '_', '-' and '.' may cause compatibility problems, as they weren't allowed in HTML 4. Though this restriction has been lifted in HTML5, an ID should start with a letter for compatibility.
function id(prefix = '', length = 7) {
let result = prefix;
for(let i = 0; i < length; i++) {
const random = Math.random();
result += String.fromCharCode(Math.floor(random * 26) + (random < .5 ? 65 : 97));
}
return result;
}
a random number between 0 and 25 is generated then added to either 65 or 97. When added to 65 it will give you an ascii code for a capital letter and when added to 97, an ascii code for a small letter.
Just use built-int crypto.randomUUID() which is supportted by all major browsers:
let uuid = crypto.randomUUID();
console.log(uuid);

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