Develop Reference

refers to a value, but is being used as a type here. Did you mean 'typeof ' ? ts(2749)

I was developing a minesweeper game in typescript. But while defining a type named Cell, I encountered an error.
Code:
Not Working
const bomb = "💣";
const flag = "🚩";
export type Cell = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | bomb | flag;
export type Board = Array<Array<Cell>>;
While defining type Cell the error raises:
'bomb' refers to a value, but is being used as a type here. Did you mean 'typeof bomb'?ts(2749)
while doing it in another way without any variable or constant works:
Fine
export type Cell = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | "💣" | "🚩";
What am I doing wrong? What is the reason?

bomb and flag and not types.
The typeof operator will give you access to the type of a value.
const bomb = "💣";
const flag = "🚩";
export type Cell = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | typeof bomb | typeof flag;

How to get substring dynamically

How can I get substring dynamically, I want to split one word into two parts one is a string and other to no,
AA112 this is my string so from sql query
SELECT substr(thisColumn, 1,2) AS String from thisTable
I am getting AA in the query the index(2) I am pasing is dynamic I am getting from some value, So here I am able to get the string now I want to get the number +1 like it is 112 then -> 113
I have tried several queries but it is not working, I have tried doing it with javascript substring but it didn't work out.
Sample output
AAA123 -> AAA and 124
AA4 -> AA and 5
BBBB8 -> BBBB and 9

const input="AA112";
var numberPattern = /\d+/g;
const number = input.match(numberPattern)[0];
const text = input.replace(number,"");
console.log(text); //AA
console.log(number); //112
const incremented = parseInt(number) + 1;
console.log(incremented);

Using LOCATE, IF,LEAST and SUBSTRING over two sub-query can achieve the output result you're looking for.
SELECT VAL,
SUBSTRING(VAL,1,FIRSTNUM-1),
SUBSTRING(VAL,FIRSTNUM,999)+1
FROM
(SELECT VAL,LEAST(V0+0,V1+0,V2+0,V3+0,V4+0,V5+0,V6+0,V7+0,V8+0,V9+0) FIRSTNUM FROM
(SELECT VAL,
IF(LOCATE(0,VAL)=0,999,LOCATE(0,VAL)) V0,
IF(LOCATE(1,VAL)=0,999,LOCATE(1,VAL)) V1,
IF(LOCATE(2,VAL)=0,999,LOCATE(2,VAL)) V2,
IF(LOCATE(3,VAL)=0,999,LOCATE(3,VAL)) V3,
IF(LOCATE(4,VAL)=0,999,LOCATE(4,VAL)) V4,
IF(LOCATE(5,VAL)=0,999,LOCATE(5,VAL)) V5,
IF(LOCATE(6,VAL)=0,999,LOCATE(6,VAL)) V6,
IF(LOCATE(7,VAL)=0,999,LOCATE(7,VAL)) V7,
IF(LOCATE(8,VAL)=0,999,LOCATE(8,VAL)) V8,
IF(LOCATE(9,VAL)=0,999,LOCATE(9,VAL)) V9 FROM mytable) A ) B;
Here I use LOCATE to find the location of the number occurrence in the value then REPLACE to change the value to 999 if it returns 0. This is essential for the next operation using LEAST because if I leave it 0, it'll return all 0 instead. The reason I use LEAST is because if you look at the 4th data example in the fiddle it's AAAAA321. This will return the result in grid like the following:
+----------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| VAL | V0 | V1 | V2 | V3 | V4 | V5 | V6 | V7 | V8 | V9 |
+----------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| AAA123 | 999 | 4 | 5 | 6 | 999 | 999 | 999 | 999 | 999 | 999 |
| AA4 | 999 | 999 | 999 | 999 | 3 | 999 | 999 | 999 | 999 | 999 |
| BBBB8 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 5 | 999 |
| AAAAA321 | 999 | 8 | 7 | 6 | 999 | 999 | 999 | 999 | 999 | 999 | <---this
| AAA45 | 999 | 999 | 999 | 999 | 4 | 5 | 999 | 999 | 999 | 999 |
+----------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
The first number occurrence is actually '3' but because I construct the query running from 0-9, I'll always get the first number in front (in this case '1' is the 8th occurrence) despite it being on the middle or last position. That's why LEAST will correctly take which number is actually located first using LOCATE function.
In the last outer query, I use the result from the LEAST function (assigned as FIRSTNUM) as the defining value for the SUBSTRING. The first substring I use it as the end location subtract by 1 to get the strings and in the second substring I use it as the first location to get the number (I end the location with 999).
Fiddle: https://www.db-fiddle.com/f/F15cxiYJxGcozYUbQukeB/5
Edit: I realized I cannot use REPLACE because if the location is like 10, it will replace 0 to 999 which makes it become 1999 instead. So I use IF.

what is the difference between Boolean('') is false and Boolean(new String(''))?

I have a doubt that both are strings why getting different Boolean values Boolean('') is false and Boolean(new String(''))?

The Boolean function returns true for all object references. new String("") creates a string object. In contrast, "" is just a string primitive; Boolean returns false for a blank string primitive.
When called as a function (rather than as a constructor), Boolean returns the result of the spec's ToBoolean abstract operation:
The abstract operation ToBoolean converts argument to a value of type Boolean according to Table 9:
+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Table 9: ToBoolean Conversions |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Argument Type | Result |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Undefined | Return false. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Null | Return false. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Boolean | Return argument. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Number | If argument is +0, −0, or NaN, return false; |
| | otherwise return true. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| String | If argument is the empty String (its length is |
| | zero), return false; otherwise return true. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Symbol | Return true. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
| Object | Return true. |
+−−−−−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−+
As you can see from the last row in the table, anything that's an object will result in true.

The following values are coerced to false because are falsy values: '', NaN, undefined, null, 0.
Everything else will be coerced to true because are truthy values.
What you're trying to do with:
Boolean('') // Coercing a primitive empty string (falsy).
And with the following:
Boolean(new String('')) // Coercing an object (truthy).

What is the purpose of =+ in JavaScript [duplicate]

What does the +d in
function addMonths(d, n, keepTime) {
if (+d) {
mean?

The + operator returns the numeric representation of the object. So in your particular case, it would appear to be predicating the if on whether or not d is a non-zero number.
Reference here. And, as pointed out in comments, here.

Operator + is a unary operator which converts the value to a number. Below is a table with corresponding results of using this operator for different values.
+----------------------------+-----------+
| Value | + (Value) |
+----------------------------+-----------+
| 1 | 1 |
| '-1' | -1 |
| '3.14' | 3.14 |
| '3' | 3 |
| '0xAA' | 170 |
| true | 1 |
| false | 0 |
| null | 0 |
| 'Infinity' | Infinity |
| 'infinity' | NaN |
| '10a' | NaN |
| undefined | NaN |
| ['Apple'] | NaN |
| function(val){ return val }| NaN |
+----------------------------+-----------+
Operator + returns a value for objects which have implemented method valueOf.
let something = {
valueOf: function () {
return 25;
}
};
console.log(+something);

It is a unary "+" operator which yields a numeric expression. It would be the same as d*1, I believe.

As explained in other answers it converts the variable to a number. Specially useful when d can be either a number or a string that evaluates to a number.
Example (using the addMonths function in the question):
addMonths(34,1,true);
addMonths("34",1,true);
then the +d will evaluate to a number in all cases. Thus avoiding the need to check for the type and take different code paths depending on whether d is a number, a function or a string that can be converted to a number.

Regex for validating ratios such as Y39.29/28h

I am trying to write a regular expression which has to adhere the following rules:
Y120.001/100.232k
↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑
| | | | | | | | This k may be any letter, is not required
| | | | | | | Another number if there was a dot
| | | | | | A dot, not required
| | | | | A number with at least one digit, not required if a letter follows
| | | | Always a slash
| | | If there's a dot, digits can follow
| | A dot, not required
| A number, at least one digit
Always Y
These strings should work:
Y120.001/1k
Y1/h
Y2039/100
Y29/47.0
These should not work:
x203/493s (Not a Y at the start)
Y/39x (No number after the Y)
Y83839 (Second half missing)
Y78/29 (Last letter missing)
This is my early attempt, but it does not work in PHP:
/^\$*(\d)*(.*(\d))\/*(.*(\d))*.$

This pattern should work:
^Y\d+(\.\d*)?/(\d+(\.\d*)?[a-z]?|[a-z])$
Demonstration

In javascript
re=/^Y\d+(\.\d+)?\/([a-z]$|\d+(\.\d+)?[a-z]?$)/
"Y120.001/1k Y1/h Y2039/100 Y29/47.0".split(" ").map(function(s) { return re.test(s) })
> [true, true, true, true]
"x203/493s Y/39x Y83839 Y78/29".split(" ").map(function(s) { return re.test(s) })
> [false, false, false, true]
This does accept Y78/29 as the trailing letter is optional.

After several iterations to correct for commented shortcomings:
/^Y\d+(?:\.\d+)?\/(?:(?:\d+(?:\.\d+)?)[A-Za-z]?|[A-Za-z])$/
Demonstration
Old Answer:
Here is a fully specific version that works well.
/^Y\d+(?:\.\d+)?\/(\d+(?:\.\d+)?)?[A-Za-z]?$/
Edited for a follow-up test in jsfiddle

^Y\d+\.?\d*/((\d+\.?\d*)[a-zA-Z]?|(\d+\.?\d*)?[a-zA-Z])$
You can check the explanation of the regex from here.

If I understand the nuances of your specification
\bY\d+(?:\.\d*)?/(?:[A-Za-z]|(?:\d+(?:\.\d+)?[A-Za-z]?))\b
I understand your specification to include that if the first dot is present, the following number(s) is/are optional; but if the 2nd dot is present, there must be at least one following number. Others seem to have interpreted that part of your requirements differently.

this pattern should work Y[\d.]+\/[\d.]*[a-z]? Demo

What about the following one?
var r = /^Y\d+(\.\d+)?\/(\d+(\.\d+)?|(\d+(\.\d+)?)?[A-Za-z])$/;
console.log(true === r.test('Y120.001/1k')); // true
console.log(true === r.test('Y1/h')); // true
console.log(true === r.test('Y2039/100')); // true
console.log(true === r.test('Y29/47.0')); // true
console.log(false === r.test('x203/493s')); // true
console.log(false === r.test('Y/39x')); // true
console.log(false === r.test('Y83839')); // true

try this:
/Y\d+\.?\d*\/\d+\.?\d*\w?/