Getting error .append is not a function - javascript

I am trying to split up a string on /* and then to split up those segments on */
So that I can separate out all of the comments as I want this code to be able to take all of the comments out of the string and then put it back together.
The problem is though I keep getting this .append error which I am pretty sure is because I have made a silly syntax error but I am struggling to find it and any help would be greatly appreciated.
JS
contents = "if for /* else */ . = == === /* return */ function"
var start = /\/\*/gi;
var end = /\*\//gi;
var commentsRemovedSec2 = [];
var commentsRemovedSec1 = contents.split(start);
console.log(commentsRemovedSec1);
for (var i = 0; i < commentsRemovedSec1.length; i++) {
var z = ""
var x = commentsRemovedSec1[i]
var y = x.split(start)
z = y[0]
commentsRemovedSec2.append(z);
};
console.log(commentsRemovedSec2);

Unfortunately .append() isn't an Array method.
Instead use the Array method .push().
commentsRemovedSec2.push(z)
The push() method adds one or more elements to the end of an array and
returns the new length of the array. MDN

Related

Using string interpolation in React.js regex function

I am having some issues using string interpolation in a regex, however I have also tried to log it to the console and I can see that I am doing it incorrectly.
I am trying to loop through an array of weather types to see if my API request returned a type of weather which requires me to add a class to one of my elements in the UI.
I iniitally thought the issue was using array[x] in the regex, but I have assigned this to a variable p and am still getting the same result.
let weatherTypes = ['rain', 'clouds', 'snow', 'clear', 'thunderstorm'];
for (var x= 0; x <= weatherTypes.length; x++) {
let p = weatherTypes[x];
console.log(p)
var searchPattern = `/${p}/i`;
var result = this.state.description.match(searchPattern);
console.log(`splash--weather-${p}`);
if(result !== null) {
var element = document.getElementById("splashContact");
element.classList.add(`splash--weather-${weatherTypes[0]}` );
}
}
The logic to add the class works when I abstract it out of the for loop so I know that part is working fine.
Can somebody please point me in the right direction?
edit Have now used backticks instead of quotation marks
searchPattern is a string so you just need to use the RegExp constructor before using it.
var searchPattern = `${p}/i`;
var searchPatternRegex = RegExp(`${searchPattern}`);

JavaScript Array.shift not working

I have been programming a system that is supposed to delete the first index of an array. Instead of changing an array from (i.e) "1,2,3,4,5" to "2,3,4,5" the console gives an error: "Uncaught TypeError: num.splice is not a function". I have heard that num.splice is not a function, it is an operation (or something) to delete the first indexed value of the array. I am confused that when I use an example code from w3Schools, there is no outputted error in the console. I don't understand why this happens.
(I have given the entire code just in case it has to do with syntax issues)
function dCrypt() {
var num = document.getElementById("demoin").value; // ex: a127
var key = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"];
var mod = 0;
var out = 0;
var prep = 0;
var pre = 0;
num.split("");
mod = num[0];
pre = key.indexOf(mod);
num.splice(0,1);
for (i=0;i <= pre;i++) {
prep += 26;
}
out = Math.floor(num + pre);
document.getElementById("demoout").innerHTML = out;
}
Thanks in advance!
When you split 'num' you have to reassign it
num = num.split("");
Referring to your link from w3schools:
The splice() method adds/removes items to/from an array, and returns the removed item(s).
As you can see the var num is string(and not an array) and has the value of the element with id demoin.
Since you are trying to splice a string and not an array. The error shows up in the console.
Solution:
Either store the value of your split in an array(it could be num itself) and then splice that array.
num = num.split("");
...
num.splice(0,1);

TypeError: 'undefined' is not an object in Javascript

I have a piece of Javascript code that assigns string of values to a string array.
Unfortunately if I try to add more than one string to the array, my UI simulator(which runs on JS code) closes unexpectedly. I have tried debugging but I cannot find anything. I am attaching that piece of code where the issue is. may be you guys could find some flaw? On the pop up button click the values I selcted on the UI should get stored in the array and I have a corressponding variable on the server side to handle this string array.
_popupButtonClick: function (button) {
var solutions = this._stateModel.get('solutionName');
var i;
var solutionsLength = solutions.length;
var selectedSolution = [solutionsLength];
this.clearPopupTimer();
if (button.position === StatusViewModel.ResponseType.Ok) {
for(i=0;i<solutionsLength;i++)
{
if(this._list.listItems[i].selected)
{
selectedSolution[i] = this._list.listItems[i].options.value;
}
}
this._stateModel.save({
selectedsolutions: selectedSolution,
viewResponse: StatusViewModel.ResponseType.Ok
});
} else {
this._stateModel.save({
viewResponse: StatusViewModel.ResponseType.Cancel
});
}
}
Change
var selectedSolution = [solutionsLength];
to
var selectedSolution = [];
This makes your array have an extra item that might be causing a crash.
Also,
you have an
if(this._list.listItems[i].selected)
{
selectedSolution[i] = this._list.listItems[i].options.value;
}
But no corresponding else, so your array has undefined values for i which are not entering the if.
Maybe adding an empty string might solve it:
if(this._list.listItems[i].selected)
{
selectedSolution[i] = this._list.listItems[i].options.value;
}
else
{
selectedSolution[i] = "";
}
The code is looking fine but there seems to be a piece of code which can cause error. For example, you are assigning var selectedSolution = [solutionsLength]; and for example solutionsLength is 5 then your loop runs for 5 times
for(i=0;i<solutionsLength;i++) // runs for 5 times
{
if(this._list.listItems[i].selected)
{
// but selectedSolution = [5]; which is on 0th index and from 1st to 4th index it is undefined
selectedSolution[i] = this._list.listItems[i].options.value;
}
}
So you can try to use push() like
selectedSolution.push(this._list.listItems[i].options.value);
and on initialization change it like,
var selectedSolution = [];
Hopefully this will solve your problem.
var selectedSolution = [solutionsLength];
keeps the value in the selectedSolution variable.
var selectedSolution = [3];
selectedSolution[0] gives the values as 3
So make it simple
var selectedSolution = [];

How to remove all characters before specific character in array data

I have a comma-separated string being pulled into my application from a web service, which lists a user's roles. What I need to do with this string is turn it into an array, so I can then process it for my end result. I've successfully converted the string to an array with jQuery, which is goal #1. Goal #2, which I don't know how to do, is take the newly created array, and remove all characters before any array item that contains '/', including '/'.
I created a simple work-in-progress JSFiddle: https://jsfiddle.net/2Lfo4966/
The string I receive is the following:
ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC
ABCD/ in the string above can change, and may be XYZ, MNO, etc.
To convert to an array, I've done the following:
var importUserRole = 'ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC';
var currentUserRole = importUserRole.split(',');
Using console.log, I get the following result:
["ABCD", "ABCD/Admin", "ABCD/DataManagement", "ABCD/XYZTeam", "ABCD/DriverUsers", "ABCD/RISC"]
I'm now at the point where I need the code to look at each index of array, and if / exists, remove all characters before / including /.
I've searched for a solution, but the JS solutions I've found are for removing characters after a particular character, and are not quite what I need to get this done.
You can use a single for loop to go through the array, then split() the values by / and retrieve the last value of that resulting array using pop(). Try this:
for (var i = 0; i < currentUserRole.length; i++) {
var data = currentUserRole[i].split('/');
currentUserRole[i] = data.pop();
}
Example fiddle
The benefit of using pop() over an explicit index, eg [1], is that this code won't break if there are no or multiple slashes within the string.
You could go one step further and make this more succinct by using map():
var importUserRole = 'ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC';
var currentUserRole = importUserRole.split(',').map(function(user) {
return user.split('/').pop();
});
console.log(currentUserRole);
You can loop through the array and perform this string replace:
currentUserRole.forEach(function (role) {
role = role.replace(/(.*\/)/g, '');
});
$(document).ready(function(){
var A=['ABCD','ABCD/Admin','ABCD/DataManagement','ABCD/XYZTeam','ABCD/DriverUsers','ABCD/RISC'];
$.each(A,function(i,v){
if(v.indexOf('/')){
var e=v.split('/');
A[i]=e[e.length-1];
}
})
console.log(A);
});
You could replace the unwanted parts.
var array = ["ABCD", "ABCD/Admin", "ABCD/DataManagement", "ABCD/XYZTeam", "ABCD/DriverUsers", "ABCD/RISC"];
array = array.map(function (a) {
return a.replace(/^.*\//, '');
});
console.log(array);
var importUserRole = 'ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC';
var currentUserRole = importUserRole.split(',');
for(i=0;i<currentUserRole.length;i++ ){
result = currentUserRole[i].split('/');
if(result[1]){
console.log(result[1]+'-'+i);
}
else{
console.log(result[0]+'-'+i);
}
}
In console, you will get required result and array index
I would do like this;
var iur = 'ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC',
arr = iur.split(",").map(s => s.split("/").pop());
console.log(arr);
You can use the split method as you all ready know string split method and then use the pop method that will remove the last index of the array and return the value remove pop method
var importUserRole = ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC';
var currentUserRole = importUserRole.split(',');
for(var x = 0; x < currentUserRole.length; x++;){
var data = currentUserRole[x].split('/');
currentUserRole[x] = data.pop();
}
Here is a long way
You can iterate the array as you have done then check if includes the caracter '/' you will take the indexOf and substact the string after the '/'
substring method in javaScript
var importUserRole = 'ABCD,ABCD/Admin,ABCD/DataManagement,ABCD/XYZTeam,ABCD/DriverUsers,ABCD/RISC';
var currentUserRole = importUserRole.split(',');
for(var x = 0; x < currentUserRole.length; x++){
if(currentUserRole[x].includes('/')){
var lastIndex = currentUserRole[x].indexOf('/');
currentUserRole[x] = currentUserRole[x].substr(lastIndex+1);
}
}

Javascript regular expressions for Query Builder

This may have been asked in the past but I couldnt find a suitable answer. What I am looking for is a method to extract parameters from an sql query such as below. The queries will always be an EXEC statement followed by the query name, and possible parameters.
Here is an example of what I may recieve
EXEC [dbo].[myProcedure] #Param1
This could also be as follows
EXEC [dbo].[myProcedure] #Param1, #Param2, #Param3
Those are the only types of queries that the input will take. As for why I am doing this, well thats another question all together, and I am pretty set on going down this route.
What I am looking for is to be able to take the above strings and produce an array of values such as
['#Param1','#Param2','#Param3',....]
I originally tried to just parese using a simple while statement but I seem to have huge issues there.
I hope this question makes sense,
Cheers,
Nico
[Edit]
Sorted this by using the following statement
function eParams(e) {
var i = e.indexOf('#');
if (i <= 0)
return;
e = e.substring(i);
var p = e.split(',');
var eList = [];
var s = '';
for (var i = 0, j = p.length - 1; i <= j; i++) {
var sP = p[i].trim();
if (sP.indexOf('#') < 0)
continue;
eList.push(sP);
}
}
var str = 'EXEC [dbo].[myProcedure] #Param1, #Param2, #Param3';
(str).match(/(#[^\s,]+)/g);
will return an array.
var s = "EXEC [dbo].[myProcedure] #Param1, #Param2, #Param3";
var i = s.indexOf('#');
var a = s.substr(i).split(/\s*,\s*/);
(error checking omitted)

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