Develop Reference

How to turn a function into a string without activation/use of any modules in javascript

Apparently this might look at a duplicate.. but let me explain the problem.For the sake of the question ALL I can assume is that my code will be run, I do not know anything about the modules(if they're fake or something) and can only trust the things that get set in instances that only my code will control(or originally set that they cannot be configured)
What I want to do is to as my heading says, to convert a function to a string.. however all my attempts at conversion depend on a module that can be overwritten by the client
Function.prototype.toString=()=>"pwned" //work of the client
//failed attempts to convert to string below
console.log(`${Object.keys}`) //"pwned"
console.log(Object.keys+'') //"pwned"
console.log(Object.keys.toLocaleString()) //"pwned"
Starting out with the only assumption I'm making(that my code is being run), I tried this below however it returns undefined(I thought returning nothing would somehow make it the default string)
//infinityLoop is a function I write(all this is inside another self calling function) and the name suggests what it does
//the concept in this example is to run the code and if it smells anything suspicious, infinite loop
try{(function(href){
var symbol=Symbol.toPrimitive, c=1, here=arguments.callee
var testObj={[symbol]:function(){return here===arguments.callee.caller?c++:infinityLoop()}}
if(testObj-0!==1 || c!==2){throw "bruh"}
function str(item){
var measure=null, unit={}, count=0
function verifier(hint){
const condition=hint!=="default" || this!==item || verifier.caller!==str || count!==0
if(condition){infinityLoop()} else{ measure=unit; count++ }
}
item[symbol]=verifier; const string=item+''
if(measure!==unit || count !==1){throw "bruh"}
delete item[symbol]; return string
}
str(Object.keys) //"undefined"
//I get to control the conversion but I still can't convert it ;-;
})()}catch{infinityLoop()}
Is it possible to convert a function to string without overwritable modules or is this a ridiculous impossible question?

This is not possible.
If you don't control and/or trust the environment that is running the code, you also cannot control and/or trust what the code does.

ES6 calling method in another class, using modules

I know there is many questions like this asked, but I have been searching for hours and can't find any answers. I have this method, which takes in a parameter, which should be ID of two selects. Using this parameter, I want to determine which select is used and execute the if statement, but to no avail. When I run it, it shows no errors in console in Chrome and it does nothing. Can anyone shed some light on it, this is the method in one export class:
static styleCircle(select) {
if(this.select === ELEMENTS.ELEMENT_COLOR_SELECT) {
var getColor = ELEMENTS.ELEMENT_COLOR_SELECT;
var colorValue = getColor.options[getColor.selectedIndex].value;
ELEMENTS.ELEMENT_STYLE_CIRCLE.style.backgroundColor = colorValue;
} else if(select == ELEMENTS.ELEMENT_BORDER_SELECT) {
var getRadius = ELEMENTS.ELEMENT_BORDER_SELECT;
var radiusValue = getRadius.options[getRadius.selectedIndex].value;
ELEMENTS.ELEMENT_STYLE_CIRCLE.style.borderRadius = radiusValue;
}
}
This is it being called in another class, on two select elements, and the class is imported at the top of the file:
ELEMENTS.ELEMENT_COLOR_SELECT.onchange = Script.styleCircle(this);
ELEMENTS.ELEMENT_BORDER_SELECT.onchange = Script.styleCircle(this);
ELEMENTS is a file with constants, which are just being used to get ID's from the HTML file. I used other methods like this, with onclick events, but none had parameters, and now I'm stuck here. Thanks in advance.

You don't want to call the functions right now but instead you probably want to pass functions. Through that you can access the proper this and pass it to styleCircle:
ELEMENTS.ELEMENT_COLOR_SELECT.onchange = function() {
Script.styleCircle(this);
};
ELEMENTS.ELEMENT_BORDER_SELECT.onchange = function() {
Script.styleCircle(this);
};
Additionally this.select is probably causing you troubles as window.select is undefined.

First step would be to try debugging and ensure select is equivalent to either of those constants. Make sure you have full branching coverage in your debugging. That would mean start by adding an else statement to that if/else if statement - it's possible that your select is not equal to either constant and so neither branch is run.

Javascript: Flexibility of function parameters?

The description of Javascript function parameters on W3Schools wasn't very clear, so I just want to clarify.
From my understanding, there isn't a type restriction; the "real value" of the parameters are passed into the method. Is there a way to pass objects or elements? Or is that what is meant by "real value"?
For example:
The function displayText meant to take input text and set a display to show a new word in the given input text, going to the next word every time it's called.
function displayText() {
var text = document.getElementById("words").value;
// Since text is initialized
// every time the method is called,
// it will always start at the beginning of the text area.
// Not sure how to fix this since making `text`
// a global variable doesn't work
var list = text.split(/[ \t\n]+/);
displayNext(list, "display");
}
There is a "helper" method, displayNext, which is supposed to shift to the next word in the list and sets the display to that word.
function displayNext(list, textboxID) {
document.getElementById(textboxID).innerHTML = list.shift();
}
This isn't working as it is intended. I'm fairly sure it's because I've mucked up something with the parameters, since displayNext sets innerHTML to null. list must have not passed properly. I'm not sure how to fix this.
I'm sure there's a more efficient way to do this, but this is a good opportunity to learn how Javascript parameters actually work, so I thought I'd ask.
JSFiddle

Based on the comments in your code, it sounds like you want displayText() to display the "next" word each time. To do that, you have to create some place to store some state about which word is the next one to display. As you have it now, you create a new array every time and always display the first word.
The simplest way is to create a variable outside your function in some lasting scope where you store the word number:
var wordNum = 0;
function displayText() {
var text = document.getElementById("words").value;
var list = text.split(/\s+/);
if (list.length !== 0) {
// make sure we aren't off the end of the list
wordNum = wordNum % list.length;
displayNext(list[wordNum++], "display");
}
}
function displayNext(text, textboxID) {
document.getElementById(textboxID).innerHTML = text;
}
For a lot more info about arguments to Javascript functions and even how you can detect what arguments were passed or overload arguments, see this answer: How to overload functions in javascript? and for more info about how arguments are passed: Javascript by reference vs. by value

Javascript code causing IE freeze

I have the below code causing Internet Explorer to freeze. It's a project that involves processing student grades as an assignment:
var array1 = StudentGradeAreadHugeList();
var nextArrayItem = function() {
var grade = array1.pop();
if (grade) {
nextArrayItem();
}
};
i hope you can help me with this.

You could show more info about the application you're trying to do. But I believe it's a matter of stack overflow (maybe you're using a big list). So, to overcome that you should modify the "nextArrayItem":
window.setTimeout (nextArrayItem, 0)
The freeze incurring mainly from the big data, but now the Event Loop will handle the Recursion process and not your Call Stack.

This is likely caused by an endless recursion. Be aware of proper handling of return values in IE:
var array1 = StudentGradeAreadHugeList();
var nextArrayItem = function() {
var grade = array1.pop();
if ( grade !== null && typeof(grade) !== "undefined" ) {
nextArrayItem();
}
};
pop() on an empty array will not return boolean false but a typeless "undefined".

There's two problems here:
You might be exceeding the call stack limit
Your if-conditional is set-up incorrectly
For the first issue:
As one of the previous responders mentioned, if you have a very large list you can exceed the limit of the call stack since you need to do a recursive call for each element. While doing setTimeout might work, it feels like a hack-y solution. I think the real issue is that your function is handling the array recursively rather than iteratively. I would recommend re-writing your function using a for-loop.
For the second issue:
Let's say in this case your array was set to [100, 90, 80]. When you invoke nextArrayItem() it will work properly the first two time, but the third time you call nextArrayItem() you are popping off the last remaining item (in this case 100) and your grade will be set to 100 which is a truthy value. Therefore, your if-conditional will pass and your function erroneously try to invoke itself again despite the fact that your array is now empty and the program should now exit the call stack.
I tried testing your code using my example in Chrome and what happens is that it will recurse one too many times and invoke pop on an empty array, which will return undefined.
You can fix this issue by changing the if conditional to check for the last element in the array after you have popped the array.
See revised code:
var nextArrayItem = function() {
var grade = array1.pop();
if (array1[array1.length-1]) {
nextArrayItem();
}
};

Programming optional ignorance

In Javascript what is the best way to handle scenarios when you have a set of arrays to perform tasks on sets of data and sometimes you do not want to include all of the arrays but instead a combination.
My arrays are labeled in this small snippet L,C,H,V,B,A,S and to put things into perspective the code is around 2500 lines like this. (I have removed code notes from this post)
if(C[0].length>0){
L=L[1].concat(+(MIN.apply(this,L[0])).toFixed(7));
C=C[1].concat(C[0][0]);
H=H[1].concat(+(MAX.apply(this,H[0])).toFixed(7));
V=V[1].concat((V[0].reduce(function(a,b){return a+b}))/(V[0].length));
B=B[1].concat((MAX.apply(this,B[0])-MIN.apply(this,B[0]))/2);
A=A[1].concat((MAX.apply(this,A[0])-MIN.apply(this,A[0]))/2);
D=D[1].concat((D[0].reduce(function(a,b){return a+b}))/(D[0].length));
S=S[1].concat((S[0].reduce(function(a,b){return a+b}))/(S[0].length));
}
It would seem counter-productive in this case to litter the code with tones of bool conditions asking on each loop or code section if an array was included in the task and even more silly to ask inside each loop iteration with say an inline condition as these would also slow down the processing and also make the code look like a maze or rabbit hole.
Is there a logical method / library to ignore instruction or skip if an option was set to false
All I have come up with so far is kind of pointless inline thing
var op=[0,1,1,0,0,0,0,0]; //options
var L=[],C=[],H=[],V=[],B=[],A=[],D=[],S=[];
op[0]&&[L[0]=1];
op[1]&&[C[0]=1,console.log('test, do more than one thing')];
op[2]&&[H[0]=1];
op[3]&&[V[0]=1];
op[4]&&[B[0]=1];
op[5]&&[A[0]=1];
op[6]&&[A[0]=1];
It works in that it sets only C[0] and H[0] to 1 as the options require, but it fails as it needs to ask seven questions per iteration of a loop as it may be done inside a loop. Rather than make seven versions of the the loop or code section, and rather than asking questions inside each loop is there another style / method?
I have also noticed that if I create an array then at some point make it equal to NaN rather than undefined or null the console does not complain
var L=[],C=[],H=[],V=[],B=[],A=[],D=[],S=[];
L=NaN;
L[0]=1;
//1
console.log(L); //NaN
L=undefined;
L[0]=1
//TypeError: Cannot set property '0' of undefined
L=null
L[0]=1
//TypeError: Cannot set property '0' of null
Am I getting warmer? I would assume that if I performed some math on L[0] when isNaN(L)===true that the math is being done but not stored so the line isn't being ignored really..

If I understand what you want I would do something like this.
var op = [...],
opchoice = {
//these can return nothing, no operation, or a new value.
'true': function(val){ /*operation do if true*/ },
'false': function(val){ /*operation do if false*/ },
//add more operations here.
//keys must be strings, or transformed into strings with operation method.
operation: function(val){
//make the boolean a string key.
return this[''+(val == 'something')](val);
}
};
var endop = [];//need this to prevent infinite recursion(loop).
var val;
while(val = op.shift()){
//a queue operation.
endop.push(opchoice.operation(val));
}
I'm sure this is not exactly what you want, but it's close to fulfilling the want of not having a ton of conditions every where.
Your other option is on every line do this.
A = isNaN(A) ? A.concat(...) : A;
Personally I prefer the other method.

It looks like you repeat many of the operations. These operations should be functions so at least you do not redefine the same function over and over again (it is also an optimization to do so).
function get_min(x)
{
return +(MIN.apply(this, a[0])).toFixed(7);
}
function get_max(x)
{
return +(MAX.apply(this, a[0])).toFixed(7);
}
function get_average(x)
{
return (x[0].reduce(function(a, b) {return a + b})) / (x[0].length);
}
function get_mean(x)
{
return (MAX.apply(this, x[0]) - MIN.apply(this, x[0])) / 2;
}
if(C[0].length > 0)
{
L = L[1].concat(get_min(L));
C = C[1].concat(C[0][0]);
H = H[1].concat(get_max(H));
V = V[1].concat(get_average(V));
B = B[1].concat(get_mean(B));
A = A[1].concat(get_mean(A);
D = D[1].concat(get_average(D));
S = S[1].concat(get_average(S));
}
You could also define an object with prototype functions, but it is not clear whether it would be useful (outside of putting those functions in a namespace).
In regard to the idea/concept of having a test, what you've found is probably the best way in JavaScript.
op[0] && S = S[1].concat(get_average(S));
And if you want to apply multiple operators when op[0] is true, use parenthesis and commas:
op[3] && (V = V[1].concat(get_average(V)),
B = B[1].concat(get_mean(B)),
A = A[1].concat(get_mean(A));
op[0] && (D = D[1].concat(get_average(D)),
S = S[1].concat(get_average(S)));
However, this is not any clearer, to a programmer, than an if() block as shown in your question. (Actually, many programmers may have to read it 2 or 3 times before getting it.)
Yet, there is another solution which is to use another function layer. In that last example, you would do something like this:
function VBA()
{
V = V[1].concat(get_average(V));
B = B[1].concat(get_mean(B));
A = A[1].concat(get_mean(A));
}
function DS()
{
D = D[1].concat(get_average(D));
S = S[1].concat(get_average(S));
}
op = [DS,null,null,VBA,null,null,...];
for(key in op)
{
// optional: if(op[key].hasOwnProperty(key)) ... -- verify that we defined that key
if(op[key])
{
op[key](); // call function
}
}
So in other words you have an array of functions and can use a for() loop to go through the various items and if defined, call the function.
All of that will very much depend on the number of combinations you have. You mentioned 2,500 lines of code, but the number of permutations may be such that writing it one way or the other will possibly not reduce the total number of lines, but it will make it easier to maintain because many lines are moved to much smaller code snippet making the overall program easier to understand.
P.S. To make it easier to read and debug later, I strongly suggest you put more spaces everywhere, as shown above. If you want to save space, use a compressor (minimizer), Google or Yahoo! both have one that do a really good job. No need to write your code pre-compressed.