# NumberField.js

    /**
     * @class Ext.form.NumberField
     * @extends Ext.form.TextField
     * Numeric text field that provides automatic keystroke filtering and numeric validation.
     * @constructor
     * Creates a new NumberField
     * @param {Object} config Configuration options
     */
    Ext.form.NumberField = function(config){
        Ext.form.NumberField.superclass.constructor.call(this, config);
    };

    Ext.extend(Ext.form.NumberField, Ext.form.TextField,  {
        /**
         * @cfg {String} fieldClass The default CSS class for the field (defaults to "x-form-field x-form-num-field")
         */
        fieldClass: "x-form-field x-form-num-field",
        /**
         * @cfg {Boolean} allowDecimals False to disallow decimal values (defaults to true)
         */
        allowDecimals : true,
        /**
         * @cfg {String} decimalSeparator Character(s) to allow as the decimal separator (defaults to '.')
         */
        decimalSeparator : ".",
        /**
         * @cfg {Number} decimalPrecision The maximum precision to display after the decimal separator (defaults to 2)
         */
        decimalPrecision : 2,
        /**
         * @cfg {Boolean} allowNegative False to require only positive numbers (defaults to true)
         */
        allowNegative : true,
        /**
         * @cfg {Number} minValue The minimum allowed value (defaults to Number.NEGATIVE_INFINITY)
         */
        minValue : Number.NEGATIVE_INFINITY,
        /**
         * @cfg {Number} maxValue The maximum allowed value (defaults to Number.MAX_VALUE)
         */
        maxValue : Number.MAX_VALUE,
        /**
         * @cfg {String} minText Error text to display if the minimum value validation fails (defaults to "The minimum value for this field is {minValue}")
         */
        minText : "The minimum value for this field is {0}",
        /**
         * @cfg {String} maxText Error text to display if the maximum value validation fails (defaults to "The maximum value for this field is {maxValue}")
         */
        maxText : "The maximum value for this field is {0}",
        /**
         * @cfg {String} nanText Error text to display if the value is not a valid number.  For example, this can happen
         * if a valid character like '.' or '-' is left in the field with no number (defaults to "{value} is not a valid number")
         */
        nanText : "{0} is not a valid number",

        // private
        initEvents : function(){
            Ext.form.NumberField.superclass.initEvents.call(this);
            var allowed = "0123456789";
            if(this.allowDecimals){
                allowed += this.decimalSeparator;
            }
            if(this.allowNegative){
                allowed += "-";
            }
            var keyPress = function(e){
                var k = e.getKey();
                if(!Ext.isIE && (e.isNavKeyPress() || k == e.BACKSPACE || (k == e.DELETE && e.button == -1))){
                    return;
                }
                var c = e.getCharCode();
                if(allowed.indexOf(String.fromCharCode(c)) === -1){
                    e.stopEvent();
                }
            };
            this.el.on("keypress", keyPress, this);
        },

        // private
        validateValue : function(value){
            if(!Ext.form.NumberField.superclass.validateValue.call(this, value)){
                return false;
            }
            if(value.length < 1){ // if it's blank and textfield didn't flag it then it's valid
                 return true;
            }
            value = String(value).replace(this.decimalSeparator, ".");
            if(isNaN(value)){
                this.markInvalid(String.format(this.nanText, value));
                return false;
            }
            var num = this.parseValue(value);
            if(num < this.minValue){
                this.markInvalid(String.format(this.minText, this.minValue));
                return false;
            }
            if(num > this.maxValue){
                this.markInvalid(String.format(this.maxText, this.maxValue));
                return false;
            }
            return true;
        },

        // private
        parseValue : function(value){
            return parseFloat(String(value).replace(this.decimalSeparator, "."));
        },

        // private
        fixPrecision : function(value){
           if(!this.allowDecimals || this.decimalPrecision == -1 || isNaN(value) || value == 0 || !value){
               return value;
           }
           // this should work but doesn't due to precision error in JS
           // var scale = Math.pow(10, this.decimalPrecision);
           // var fixed = this.decimalPrecisionFcn(value * scale);
           // return fixed / scale;
           //
           // so here's our workaround:
           var scale = Math.pow(10, this.decimalPrecision+1);
           var fixed = this.decimalPrecisionFcn(value * scale);
           fixed = this.decimalPrecisionFcn(fixed/10);
           return fixed / (scale/10);
        },

        // private
        decimalPrecisionFcn : function(v){
            return Math.floor(v);
        }
    });

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