How to get all variables and search through their values in JavaScript

getAllVariables.js

function getAllVariables(){
    var searchVarByValue = function(searchString){
        var values = Object.keys(this.ValueToVar);
        var findings = [];
        for (var i=0; i< values.length; i++){
            if (values[i] == undefined)
                continue;
            var position = values[i].toLowerCase().indexOf(searchString.toLowerCase());
            if (position != -1){
                findings.push({ 'variable': this.ValueToVar[values[i]], 'value' : values[i] });
            }
        }
        return findings;
    }
    
    var returnObject = {};
    returnObject.VarToValue = [];
    returnObject.ValueToVar = [];
    returnObject.Vars = [];
    returnObject.Values = [];
    returnObject.search = searchVarByValue;
    for (var variableName in this) {
        try{
            var value = JSON.stringify(this[variableName]);
            returnObject.VarToValue[variableName] = value;
            if (this[variableName] != null){
                returnObject.ValueToVar[value] = variableName;
                returnObject.Values.push(value);
            }
            returnObject.Vars.push(variableName);
        } catch{
            continue;
        }    
    }
    return returnObject;
}