Clarify this Javascript ternary

Can someone split this nested ternary into multiple ternaries or other code or explain it in English? I've never come across a nested ternary like this so I'm not sure the order of operations:

var EqualizeCheck = (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) ? (EqualizeCompleteTime != "") ? (EqualizeCompleteTime <= CurrentDateTime) ? true : false : false : true;

There you go:

```
let EqualizeCheck;

if (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) {
if (EqualizeCompleteTime != "") {
if (EqualizeCompleteTime <= CurrentDateTime) {
EqualizeCheck = true;
} else {
EqualizeCheck = false;
}
} else {
EqualizeCheck = false;
}
} else {
EqualizeCheck = true;
}
```

I understand that it wasn't you who wrote this, but I should point out that nesting so many ternary expressions is a bad practice, and one that leads to unreadable code.

To get better idea just break it and try to apply `if-else` then you can understand easily. And also the thing mentioned by @Sagi Rika is correct, that nesting of many ternary expressions reduce the code readbilty which leads to difficult in understanding.

First lets break your ternary expressions as below:

var EqualizeCheck = (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON)
? (EqualizeCompleteTime != "")
? (EqualizeCompleteTime <= CurrentDateTime)
? true
: false
: false
: true;


If you break it using `if-else` then it will be like as below:

var EqualizeCheck;

if (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) {
if (EqualizeCompleteTime != "") {
if (EqualizeCompleteTime <= CurrentDateTime) {
EqualizeCheck = true;
} else {
EqualizeCheck = false;
}
} else {
EqualizeCheck = false;
}
} else {
EqualizeCheck = true;
}


To understand better let's take an example using `if-else`. Its like if the age is greater than than 18 then `canVote` will be `true` otherwise `canVote` will be `false`

var age = 19;
var canVote;

if (age > 18) {
canVote = 'yes';
} else {
canVote = 'no';
}

If we write the above code using ternary expressions then that will be like:

var age = 19;
var canVote = age > 18 ? 'yes' : 'no';

To work through it step by step, first separate the most nested condition (Look for a complete `condition ? value : value` statement) In this case that's this bit:

> var EqualizeCheck = (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) ? (EqualizeCompleteTime != "") ? **(EqualizeCompleteTime <= CurrentDateTime) ? true : false** : false : true;

Separate that out and repeat for each ternary condition, until you have something like this:

```
// Condition 1:
(IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) ?
// Condition 1 == true, check the next condition
// Condition 2:
(EqualizeCompleteTime != "") ?
// Condition 2 == true, check the next condition
// Condition 3:
(EqualizeCompleteTime <= CurrentDateTime) ?
// Condition 3 == true, return true
true :
// Condition 3 == false, return false
false :
// Condition 2 == false, return false
false :
// Condition 1 == false, return true
true;
```

Since this essentially boils down to two success conditions (Either where condition 1 is false, or where condition 2 and 3 are both true), you can vastly simplify it to this:

```
var EqualizeCheck =
!IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) ||
(
EqualizeCompleteTime != "" &&
EqualizeCompleteTime <= CurrentDateTime
)
```

This is the more readable friendly version of the above ternary oparator.

const EqualizeCheck = (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON) ?
((EqualizeCompleteTime != "") ? ((EqualizeCompleteTime <= CurrentDateTime) ? true : false) : false) : true;

If you divide that into a several ternary operator statements, it will looks as follows. I hope this format is easy to understand.

const EqualizeValueCheck = (IIO.ReadDigitalInput(IO_GROUP_CHARGERS, subGroupName, IO_ITEM_ENABLEEQUALIZE) == IO_INPUT_ON);
const EqualizeCompleteTimeCheck = (EqualizeCompleteTime <= CurrentDateTime) ? true : false;
const EqualizeCompleteTimeEmptyValueCheck = (EqualizeCompleteTime != "") ? EqualizeCompleteTimeCheck : false;
const EqualizeCheck = (EqualizeValueCheck) ? EqualizeCompleteTimeEmptyValueCheck : false;