Develop Reference

Converting number string to comma version

I have a Angular 2 / Typescript application string that contains number representations such as the following...
10000
10000.50
-10000
-10000.50
0
I want to add in commas after the thousand mark, for example...
10,000
10,000.50
-10,000
-10,000.50
0
What is the best way to do this?
I have tried some other answers but nothing is quite right.
For example this.value.toString().replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,"); and this.value.toLocaleString(); don't seem to handle both the comman and decimal point.

Have you tried
var some_string_value = '-10000.50';
parseFloat(some_string_value).toLocaleString()
?

Use "indexOf('.')",splice to two part,then use the method you found.
function addComma(num){
//some type check here
var numStr = num.toString();
var intEnd = numStr.indexOf('.');
var onePart =numStr,otherPart ='';
if(intEnd !== -1){
var onePart = numStr.slice(0,intEnd);
var otherPart = numStr.slice(intEnd);
}
return onePart.replace(/(\d)(?=(?:\d{3})+$)/g, '$1,')+otherPart;
}

You can use a pipe, you can find a full answer to your question here: Add Comma Separated Thousands to Number Inputs in Angular2

What's the best way to mask a credit card in JavaScript?

In Node, I need to turn a credit card into something like this before rendering the view layer: ************1234.
Without loops and ugliness is there a utility or one liner for this? The credit card can potentially look one of these ways:
1234567898765432
1234-5678-9876-5432
1234 5678 9876 5432

Here's one way with Ramda and some RegEx:
var ensureOnlyNumbers = R.replace(/[^0-9]+/g, '');
var maskAllButLastFour = R.replace(/[0-9](?=([0-9]{4}))/g, '*');
var hashedCardNumber = R.compose(maskAllButLastFour, ensureOnlyNumbers);
hashedCardNumber('1234567898765432'); // ************5432
Demo : http://jsfiddle.net/7odv6kfk/

No need for a regex:
var cc='1234-5678-9012-3456';
var masked = '************'+cc.substr(-4); // ************3456
Will work for any format provided the last four digits are contiguous.

This is for everyone who said they didn't need another way to mask a credit card. This solution will append the last 4 chars of the card number with asterisk.
var cardNumber = '4761640026883566';
console.log(maskCard(cardNumber));
function maskCard(num) {
return `${'*'.repeat(num.length - 4)}${cardNumber.substr(num.length - 4)}`;
}
jsfiddle example

I use this function that is useful for me, because mask the credit card number and format it in blocks of four characters like this **** **** **** 1234, here the solution:
const maskCreditCard = (card) => {
return card
.replace(/.(?=.{5})/g, "*")
.match(/.{1,4}/g)
.join(" ");
};

Here's plain JavaScript using Regex with lookahead
var cardNumbers = [
"1234567898765432",
"1234-5678-9876-5432",
"1234 5678 9876 5432"
];
console.log(cardNumbers.map(maskCardNumber));
//> ["************5432", "************5432", "************5432"]
function maskCardNumber(cardNumber) {
return cardNumber.replace(/^[\d-\s]+(?=\d{4})/, "************");
};
Unlike AllienWebguy's implementation:
doesn't require an external library
does everything in one replace() call
replaces whatever number of digits with the constant number of asterisks (it should be a bit faster, but it may not be what you want)
supports only described formats (will not work, for example, with "1B2C3D4E5F6G7H89876-5432" or "1234+5678+9876=54-32")

Remove non digits, generate an asterisk string of that length - 4, append the last 4:
var masked = Array(cc.replace(/[^\d]/g, "").length - 3).join("*") + cc.substr(cc.length - 4);
Or to include space/hyphens in the mask:
var masked = Array(cc.length - 3).join("*") + cc.substr(cc.length - 4);

How to avoid parsing address as float in Javascript

I am working on javascript code that parses a tab delimited document. In order to facilitate searching I need to convert those properties that are a number to a float. However, mixed fields (like an address) should maintain the status of a String.
for(var i2=0;i2<line1.length;i2++){
var test = local[i2];
if(! (typeof test === 'undefined')){
test = test.trim();
};
var parsed = parseFloat(test);
if(!isNaN(parsed)){
if(line1[i2] === "Site Address")
console.log("Number before:"+local[i2]+" After:"+parsed);
object[line1[i2]]=parsed;
}
else{
if(line1[i2] === "Site Address")
console.log("before:"+local[i2]+" After:"+test);
object[line1[i2]]=test;
}
}
This seems to work ok unless there are both numbers and chars like the following....
Number before:1752 E MAIN ST After:1752
Is there a way to do this where the above is not seen as explicitly a number?

You can use the unary + operator:
var parsed = +test;
The parseFloat() function is OK with strings that start with a valid number that's followed by non-numeric stuff, as you've discovered.
If that seems too "hackery" you can also use the Number constructor:
var parsed = Number( test );

You haven't provided very much test data, so answers may not be very good. You can try using a regular expression so that only things that look like numbers are treated as numbers, e.g.
var isNum = /^\d+(\.\d+)?$/;
var test = line1[i2];
parsed = isNum.test(test)? parseFloat(test) : test;
The variable "test" would probaby be better named "item" or "value" or similar.

How to achieve String Manipulation in JavaScript

The problem statement is like this: I have a contract. On renewal on every month the contract name should append with renewal identifier. For example at beginning the name is myContract then on first renewal name should be myContract-R1, next renewal name should be myContract-R2 and so on.. On each renewal, the name should automatically change. So in Jquery how can I do this?

This is a JavaScript question, not a jQuery question. jQuery adds little to JavaScript's built-in string manipulation.
It sounds like you want to take a string in the form "myContract" or "myContract-Rx" and have a function that appends "-R1" (if there's no "-Rx" already) or increments the number that's there.
There's no shortcut for that, you have to do it. Here's a sketch that works, I expect it could be optimized:
function incrementContract(name) {
var match = /^(.*)-R([0-9]+)$/.exec(name);
if (match) {
// Increment previous revision number
name = match[1] + "-R" + (parseInt(match[2], 10) + 1);
}
else {
// No previous revision number
name += "-R1";
}
return name;
}
Live copy

You can use a regular expression for this:
s = s.replace(/(-R\d+)?$/, function(m) {
return '-R' + (m.length === 0 ? 1 : parseInt(m.substr(2), 10) + 1);
});
The pattern (-R\d+)?$ will match the revision number (-R\d+) if there is one (?), and the end of the string ($).
The replacement will return -R1 if there was no revision number before, otherwise it will parse the revision number and increment it.

how you get renewal number? Calculating from date, or getting from database?
var renewal = 1,
name = 'myContract',
newname = name+'R'+renewal;
or maybe like
$(function(){
function renew(contract){
var num_re = /\d+/,
num = contract.match(num_re);
if (num==null) {
return contract+'-R1';
} else {
return contract.replace(num_re,++num[0]);
}
}
var str = 'myContract';
new_contract = renew(str); // myContract-1
new_contract = renew(new_contract); // myContract-2
new_contract = renew(new_contract); // myContract-3
});
Here jQuery can't help you. It's pure JavaScript working with strings
P.S. I have here simple reg exp, that's not concrete for your example (but it works). Better use reg-exp from example of T.J. Crowder

javascript parseFloat '500,000' returns 500 when I need 500000

How would it be a nice way of handling this?
I already thought on removing the comma and then parsing to float.
Do you know a better/cleaner way?
Thanks

parseFloat( theString.replace(/,/g,'') );

I don't know why no one has suggested this expression-
parseFloat( theString.replace(/[^\d\.]/g,'') );
Removes any non-numeric characters except for periods. You don't need custom functions/loops for this either, that's just overkill.

Nope. Remove the comma.

You can use the string replace method, but not in a one liner as a regexp allows.
while(str.indexOf(',')!=-1)str= str.replace(',','');
parseFloat(str);
Or to make a single expression without a regexp=
return parseFloat(str.split(',').join(''));
I'd use the regexp.

I don't have enough reputation to add a comment, but for anyone wondering on the performance for regex vs split/join, here's a quick fiddle: https://jsfiddle.net/uh3mmgru/
var test = "1,123,214.19";
var t0 = performance.now();
for (var i = 0; i < 1000000; i++)
{
var a = parseFloat(test.replace(/,/g,''));
}
var t1 = performance.now();
document.write('Regex took: ' + (t1 - t0) + ' ms');
document.write('<br>')
var t0 = performance.now();
for (var i = 0; i < 1000000; i++)
{
var b = parseFloat(test.split(',').join(''));
}
var t1 = performance.now();
document.write('Split/join took: ' + (t1 - t0) + ' ms');
The results I get are (for 1 million loops each):
Regex: 263.335 ms
Split/join: 1035.875 ms
So I think its safe to say that regex is the way to go in this scenario

Building on the idea from #kennebec, if you want to make sure that the commas are correct, and you don't want to replace commas, you could try something like this:
function myParse(num) {
var n2 = num.split(",")
out = 0
for(var i = 0; i < n2.length; i++) {
out *= 1000;
out += parseFloat(n2[i])
}
return out
}
alert(myParse("1,432,85"));
// Returns 1432085, as the comma is misplaced.
It may not be as fast, but you wanted alternatives :)

What about a simple function to solve most of the common problems?
function getValue(obj) {
Value = parseFloat( $(obj).val().replace(/,/g,'') ).toFixed(2);
return +Value;
}
The above function gets values from fields (using jQuery) assuming the entered values are numeric (I rather validate fields while user is entering data, so I know for sure field content is numeric).
In case of floating point values, if well formatted in the field, the function will return a float point value correctly.
This function is far from complete, but it quickly fix the "," (comma) issue for values entered as 1,234.56 or 1,234,567. It will return valid number as far the content is numeric.
The + (plus) sign in front of the variable Value in the return command is a "dirty trick" used in JavaScript to assure the variable content returned will be numeric.
it is easy to modify the function to other purposes, such as (for instance), convert strings to numeric values taking care of the "," (comma) issue:
function parseValue(str) {
Value = parseFloat( str.replace(/,/g,'') ).toFixed(2);
return +Value;
}
Both operations can even be combined in one function. I.e.:
function parseNumber(item,isField=false) {
Value = (isField) ? parseFloat( $(item).val().replace(/,/g,'') ).toFixed(2) : parseFloat( item.replace(/,/g,'') ).toFixed(2)
return +Value;
}
In such case, if function is called result = parseNumber('12,092.98'); it will parse the value as it is a String. But if called as result = parseNumber('#MyField', true); it will try to obtain the value from '#MyField'.
As I said before, such functions are far from complete, and can be expanded in many ways. One idea is to check the first character of the given parameter (string) and decide based on the string format where to obtain the value to be parsed (if 1st character is = '#' then it is an ID from a DOM object, otherwise, if it begins with a number, it must be a string to be parsed).
Try it... Happy coding.