Why do sets with intervals of A-z return symbols in REGEX?

Question

Setting:

const texto = 'ABC [abc] a-c 1234';

console.log(texto.match(/[A-z]/g))

• Why the set of A(maiúsculo) until z(minusculo), that is to say, /[A-z]/g returned me to [ and ]?
• The result should not be: [A, B, C, a, b, c, a, c]?

Answer 1

[A-z] will match ASCII characters in the sequence of A to z. If you look at ascii table below you will see that there are several other characters between A and z (including the square brackets [] that you don’t want).

How you wish to marry only uppercase and lowercase letters, from A to Z and of a to z, the correct would be to use [a-zA-Z].

const texto = 'ABC [abc] a-c 1234';
console.log(texto.match(/[a-zA-Z]/g))

Answer 2

The crease or intervals follow the table Unicode.

I defined that my set should be A(maiúsculo) até z(minusculo), there are symbols in the middle of that range. It’s them: [ \ ] ^ _ `

Look at the Unicode table:

Note:

The first 127 characters of the Unicode table are the same as in the table ASCII