I have some JavaScript code that gives this error:
Uncaught TypeError: Cannot read property 'value' of undefined
Here is my code:
var i1 = document.getElementById('i1');
var i2 = document.getElementById('i2');
var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] };
if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; }
if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; }
What does this error mean?
Seems like one of your values, with a property key of 'value' is undefined. Test that i1, i2and __i are defined before executing the if statements:
var i1 = document.getElementById('i1');
var i2 = document.getElementById('i2');
var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] };
if(i1 && i2 && __i.user && __i.pass)
{
if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; }
if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; }
}
Either document.getElementById('i1'), document.getElementById('i2'), or document.getElementsByName("username")[0] is returning no element. Check, that all elements exist.
Try this, It always works, and you will get NO TypeError:
try{
var i1 = document.getElementById('i1');
var i2 = document.getElementById('i2');
var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] };
if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; }
if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; }
}catch(e){
if(e){
// If fails, Do something else
}
}
First, you should make sure that document.getElementsByName("username")[0] actually returns an object and not "undefined". You can simply check like
if (typeof document.getElementsByName("username")[0] != 'undefined')
Similarly for the other element password.
The posts here help me a lot on my way to find a solution for the Uncaught TypeError: Cannot read property 'value' of undefined issue.
There are already here many answers which are correct, but what we don't have here is the combination for 2 answers that i think resolve this issue completely.
function myFunction(field, data){
if (typeof document.getElementsByName("+field+")[0] != 'undefined'){
document.getElementsByName("+field+")[0].value=data;
}
}
The difference is that you make a check(if a property is defined or not) and if the check is true then you can try to assign it a value.
You can just create a function to check if the variable exists, else will return a default value :
function isSet(element, defaultVal){
if(typeof element != 'undefined'){
return element;
}
console.log('one missing element');
return defaultVal;
}
And use it in a variable check:
var variable = isSet(variable, 'Default value');
You code looks like automatically generated from other code - you should check that html elements with id=i1 and i2 and name=username and password exists before processing them.
Related
Here is my code, where the if condition used that approach.
if( validation.isElementInArray($scope.inputBox, $scope.comments) )
{
$scope.error_msg = " ";
$scope.comments.push($scope.inputBox);
$scope.inputBox = '';
}
else
{
$scope.error_msg = "Name can't be Same";
}
validation.isElementInArray($scope.inputBox, $scope.comments) works same as you do
$scope.comments.indexOf($scope.inputBox) !== -1
Which means that the element $scope.inputBox exist in $scope.comments. Thus, looking at your condition you should be pushing the element in $scope.comments when $scope.inputBox do not exist in it. So, it should be,
if (!validation.isElementInArray($scope.inputBox, $scope.comments)){
$scope.error_msg = ' ';
$scope.comments.push($scope.inputBox);
$scope.inputBox = '';
}
else {
$scope.error_msg = 'Name can\'t be Same';
}
I get the following error from the console: "TypeError: Cannot read property '0' of undefined", it has something to do with the array but I cannot find the mistake.
module.exports =
{
create_creeps: function()
{
var aHarvester = [[TOUGH,TOUGH, MOVE, CARRY, WORK, MOVE]["harvester"]];
Spawn.prototype.createMyCreep = function(aCreep,sRole) {
if (!Game.spawns.Spawn1.spawning){
var nameCount = 0;
var name = null;
while(name == null)
{
nameCount++;
var tryName = sRole + nameCount;
if(Game.creeps[tryName] == undefined)
name = tryName;
}
var dbg= this.canCreateCreep(aCreep, name);
if(dbg == OK) {
console.log("Creating creep " + sRole);
return this.createCreep(aCreep , name,{ role:sRole });
} else {
console.log("error "+dbg+" "+sRole);
}
}
};
Game.spawns.Spawn1.createMyCreep(aHarvester[0],aHarvester[1][0]);
};
}
Please separate arrays with a comma
So
[[TOUGH,TOUGH, MOVE, CARRY, WORK, MOVE]["harvester"]]
Should be
[[TOUGH,TOUGH, MOVE, CARRY, WORK, MOVE],["harvester"]]
Let's say I have a following template:
"foo['x'] = '{{ myVar }}';"
Is there an angular way of checking if evaluating this against my current scope will give myVar some value ? I've got an array of such small templates and I only want to include them in the document when values are truthy. I was hoping either $interpolate, $parse or $eval might come in handy here. I know for sure that $interpolate is useless. What about the other two ? Maybe it's at least possible to get the name of the assigned value/expression ?
EDIT
I wasn't specific enough. What I was trying to achieve, was checking in advance if for example template '{{ myVar }}' evaluated against the current scope will return an empty string or value of the scope variable (if it exists). The case was really specific - when traversing an array of short templates I wanted to know if a template will return as an empty string or not, and only include it in my final html if it doesn't.
I'm not sure what are you trying to achieve, but to if you want to check if myVar is truthy in current scope, you can:
{{myVar ? "aw yiss" : "nope"}}
Evaluates to "aw yiss" if myVar is truthy and "nope" otherwise.
I ended up with a modified $interpolate provider but maybe someone knows a shorter solution :
app.provider('customInterpolateProvider', [
function $InterpolateProvider() {
var startSymbol = '{{';
var endSymbol = '}}';
this.startSymbol = function(value){
if (value) {
startSymbol = value;
return this;
} else {
return startSymbol;
}
};
this.endSymbol = function(value){
if (value) {
endSymbol = value;
return this;
} else {
return endSymbol;
}
};
this.$get = ['$parse', '$sce', function($parse, $sce) {
var startSymbolLength = startSymbol.length,
endSymbolLength = endSymbol.length;
function $interpolate(text, mustHaveExpression, trustedContext, allOrNothing) {
allOrNothing = !!allOrNothing;
var startIndex,
endIndex,
index = 0,
expressions = [],
parseFns = [],
textLength = text.length,
exp;
var getValue = function (value) {
return trustedContext ?
$sce.getTrusted(trustedContext, value) :
$sce.valueOf(value);
};
var stringify = function (value) {
if (value == null) {
return '';
}
switch (typeof value) {
case 'string':
break;
case 'number':
value = '' + value;
break;
default:
value = angular.toJson(value);
}
return value;
};
var parseStringifyInterceptor = function(value) {
try {
return stringify(getValue(value));
} catch(err) {
console.err(err.toString());
}
};
while(index < textLength) {
if ( ((startIndex = text.indexOf(startSymbol, index)) !== -1) &&
((endIndex = text.indexOf(endSymbol, startIndex + startSymbolLength)) !== -1) ) {
exp = text.substring(startIndex + startSymbolLength, endIndex);
expressions.push(exp);
parseFns.push($parse(exp, parseStringifyInterceptor));
index = endIndex + endSymbolLength;
} else {
break;
}
}
if (!expressions.length && !text.contains(startSymbol) && !text.contains(endSymbol)) {
expressions.push(text);
}
if (!mustHaveExpression) {
var compute = function(values) {
for(var i = 0, ii = expressions.length; i < ii; i++) {
if (allOrNothing && angular.isUndefined(values[i])) {
return;
}
expressions[i] = values[i];
}
return expressions.join('');
};
return angular.extend(function interpolationFn(context) {
var i = 0;
var ii = expressions.length;
var values = new Array(ii);
try {
if (ii && !parseFns.length) {
return expressions[0];
} else {
for (; i < ii; i++) {
values[i] = parseFns[i](context);
}
return compute(values);
}
} catch(err) {
console.err(err.toString());
}
}, {
exp: text,
expressions: expressions,
$$watchDelegate: function (scope, listener, objectEquality) {
var lastValue;
return scope.$watchGroup(parseFns, function interpolateFnWatcher(values, oldValues) {
var currValue = compute(values);
if (angular.isFunction(listener)) {
listener.call(this, currValue, values !== oldValues ? lastValue : currValue, scope);
}
lastValue = currValue;
}, objectEquality);
}
});
}
}
return $interpolate;
}];
}
]);
Lines below were added because in some cases I have a predefined text in my short template and I always want to render it :
if (!expressions.length && !text.contains(startSymbol) && !text.contains(endSymbol)) {
expressions.push(text);
}
if (ii && !parseFns.length) {
return expressions[0];
} else {
Some days ago, Cherniv gave to me this tip:
var name = "Nora";
var names:Array = ["Mary", "Porter", "Nora", "Flint", "Elsa", "Clair",...];
if( names.indexOf( name ) > -1 )
{
// Success
}
Now, I can't check the existence of "Nora" in this array:
var names:Array = [{label:"Mary"}, {label:"Porter"},{label:"Nora"}, ...];
I'll appreciate any help.
Cheers.
UPDATE:
Now it's working. I did use:
for each (var obj:Object in list)
{
if (obj.label == compList.text)
{
updateList = 1;
break;//stops the loop;
}
}
if (updateList == 1)
{
removeCompany();
}
else
{
var nativeAlert:NativeAlert = new NativeAlert();
nativeAlert.alert("You can't update the name!");
}
Is this OK or is an ugly solution?
Thanks
for each( var obj : Object in names )
{
if( obj.label == "Nora" )
{
// Success;
break;//stops the loop;
}
}
I can make it more complex/flexible if you wish.
I have a massive validate function in my backbone model that could be simplified if only I could detect the attribute I'm testing against. There are a few ideas of how I can think to approach this problem, but they all rely on knowing the attribute name I'm testing, without hardcoding it as I am in the id variable below.
Here is an example:
validate : function(attr){
var t = this;
if(attr.user1DobMonth && attr.user1DobMonth != t.get('user1DobMonth')){
var val = jQuery.trim(attr.user1DobMonth.toLowerCase()),
id = 'user1DobMonth',
error = {
attr : id
};
if(val === 'select'){
return error;
}
}
if(attr.user2DobMonth && attr.user2DobMonth != t.get('user2DobMonth')){
var val = jQuery.trim(attr.user2DobMonth.toLowerCase()),
id = 'user2DobMonth',
error = {
attr : id
};
if(val === 'select'){
return error;
}
}
}