Devise de formatage automatique avec Jquery

Formatez automatiquement le champ de saisie de la devise avec des virgules et des décimales si nécessaire. Le texte est automatiquement formaté avec des virgules et le curseur est replacé là où l'utilisateur s'est arrêté après le formatage par rapport au déplacement du curseur à la fin de l'entrée. La validation se fait sur KeyUp et une validation finale se fait sur blur.

HTML

<input type="text" class="currency">

Javascript

$(".currency").on({
    keyup: function() {
        let input_val = $(this).val();
        input_val = numberToCurrency(input_val);
        $(this).val(input_val);
    },
    blur: function() { 
        let input_val = $(this).val();
        input_val = numberToCurrency(input_val, true, true);
        $(this).val(input_val);
    }
});

var numberToCurrency = function (input_val, fixed = false, blur = false) {
    // don't validate empty input
    if(!input_val) {
        return "";
    }
    
    if(blur) {
        if (input_val === "" || input_val == 0) { return 0; }
    }

    if(input_val.length == 1) {
        return parseInt(input_val);
    }

    input_val = ''+input_val;
    
    let negative = '';
    if(input_val.substr(0, 1) == '-'){
        negative = '-';
    }
    // check for decimal
    if (input_val.indexOf(".") >= 0) {
        // get position of first decimal
        // this prevents multiple decimals from
        // being entered
        var decimal_pos = input_val.indexOf(".");

        // split number by decimal point
        var left_side = input_val.substring(0, decimal_pos);
        var right_side = input_val.substring(decimal_pos);

        // add commas to left side of number
        left_side = left_side.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",");

        if(fixed && right_side.length > 3) {
            right_side = parseFloat(0+right_side).toFixed(2);
            right_side =  right_side.substr(1, right_side.length);
        }

        // validate right side
        right_side = right_side.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",");

        // Limit decimal to only 2 digits
        if(right_side.length > 2) {
            right_side = right_side.substring(0, 2);
        }
    
        if(blur && parseInt(right_side) == 0) {
            right_side = '';
        }

        // join number by .
        // input_val = left_side + "." + right_side;

        if(blur && right_side.length < 1) {
            input_val = left_side;
        } else {
            input_val = left_side + "." + right_side;
        }
    } else {
        // no decimal entered
        // add commas to number
        // remove all non-digits
        input_val = input_val.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",");
    }

    if(input_val.length > 1 && input_val.substr(0, 1) == '0' && input_val.substr(0, 2) != '0.' ) {
        input_val = input_val.substr(1, input_val.length);
    } else if(input_val.substr(0, 2) == '0,') {
        input_val = input_val.substr(2, input_val.length);
    }
    
    return negative+input_val;
};
Demo
<!DOCTYPE html>
<html lang="en">
<head>
    <title>Bfotool Demo</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
</head>
<body>
    <div class="container">
        <div class="row">
            <div class="col-md-12">
                <br><br>
                <div class="form-group">
                    <label for="usr">Enter Amount:</label>
                    <input type="text" class="form-control currency">
                </div>
            </div>
        </div>
    </div>

    <script>
        $(".currency").on({
            keyup: function() {
                let input_val = $(this).val();
                input_val = numberToCurrency(input_val);
                $(this).val(input_val);
            },
            blur: function() { 
                let input_val = $(this).val();
                input_val = numberToCurrency(input_val, true, true);
                $(this).val(input_val);
            }
        });

        var numberToCurrency = function (input_val, fixed = false, blur = false) {
            // don't validate empty input
            if(!input_val) {
                return "";
            }
            
            if(blur) {
                if (input_val === "" || input_val == 0) { return 0; }
            }
        
            if(input_val.length == 1) {
                return parseInt(input_val);
            }

            input_val = ''+input_val;
            
            let negative = '';
            if(input_val.substr(0, 1) == '-'){
                negative = '-';
            }
            // check for decimal
            if (input_val.indexOf(".") >= 0) {
                // get position of first decimal
                // this prevents multiple decimals from
                // being entered
                var decimal_pos = input_val.indexOf(".");

                // split number by decimal point
                var left_side = input_val.substring(0, decimal_pos);
                var right_side = input_val.substring(decimal_pos);

                // add commas to left side of number
                left_side = left_side.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",");

                if(fixed && right_side.length > 3) {
                    right_side = parseFloat(0+right_side).toFixed(2);
                    right_side =  right_side.substr(1, right_side.length);
                }

                // validate right side
                right_side = right_side.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",");

                // Limit decimal to only 2 digits
                if(right_side.length > 2) {
                    right_side = right_side.substring(0, 2);
                }
            
                if(blur && parseInt(right_side) == 0) {
                    right_side = '';
                }

                // join number by .
                // input_val = left_side + "." + right_side;

                if(blur && right_side.length < 1) {
                    input_val = left_side;
                } else {
                    input_val = left_side + "." + right_side;
                }
            } else {
                // no decimal entered
                // add commas to number
                // remove all non-digits
                input_val = input_val.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",");
            }

            if(input_val.length > 1 && input_val.substr(0, 1) == '0' && input_val.substr(0, 2) != '0.' ) {
                input_val = input_val.substr(1, input_val.length);
            } else if(input_val.substr(0, 2) == '0,') {
                input_val = input_val.substr(2, input_val.length);
            }
            
            return negative+input_val;
        };
    </script>
</body>
</html>