Angular has its own unique way of handling regular expressions through its TypeScript

Question

Angular has its own unique way of handling regular expressions through its TypeScript

Considering the creation of an enum to store various regex patterns in my application for enhanced code reuse.

For example:

export enum Regex {
    ONE_PATTERN = /^[example]+$/g,
    ANOTHER_PATTERN = /^[test]{5,7}$/g
}

However:

Encountering the TS90010 error when not using string literals: Type RegExp is not assignable to type Regex.
Unable to use these patterns in a pattern attribute on inputs if using string literals.

For instance:

<input ngModel="..." pattern="{{ANOTHER_PATTERN}}" .../>

Is this approach advisable for storing regex patterns in this manner?

regex angular typescript

Answer 1

Answer №1

It is not possible to assign a regular expression (`RegExp`) to an enumeration (`enum`), as enumerations can only be either numeric or string-based.

If you want to store the `RegExp`, you have two options:

Option A - Store the `RegExp` as a string in an enumeration

enum RegExpEnum {
    ONE_DANK_REGEX = "^[dank]+$",
    FIVE_OUT_OF_SEVEN = "^[meme]{5,7}$"
}

Option B - Store the `RegExp` in a class/variable

class RegexClass {
    public static readonly ONE_DANK_REGEX = /^[dank]+$/g;
    public static readonly FIVE_OUT_OF_SEVEN = /^[meme]{5,7}$/g;
}

In both cases, you will need to reference the containing enumeration or class in your component by assigning it to a local variable.

@Component({ ... })
public class MyComponent {
    availableRegex = RegExpEnum; // or RegexClass
}

You can then access it in the HTML part of your component.

<input [(ngModel)]="name" [pattern]="availableRegex.ONE_DANK_REGEX"/>

DEMO

Answer 2

It is not possible to assign a regular expression (`RegExp`) to an enumeration (`enum`), as enumerations can only be either numeric or string-based.

If you want to store the `RegExp`, you have two options:

Option A - Store the `RegExp` as a string in an enumeration

enum RegExpEnum {
    ONE_DANK_REGEX = "^[dank]+$",
    FIVE_OUT_OF_SEVEN = "^[meme]{5,7}$"
}

Option B - Store the `RegExp` in a class/variable

class RegexClass {
    public static readonly ONE_DANK_REGEX = /^[dank]+$/g;
    public static readonly FIVE_OUT_OF_SEVEN = /^[meme]{5,7}$/g;
}

In both cases, you will need to reference the containing enumeration or class in your component by assigning it to a local variable.

@Component({ ... })
public class MyComponent {
    availableRegex = RegExpEnum; // or RegexClass
}

You can then access it in the HTML part of your component.

<input [(ngModel)]="name" [pattern]="availableRegex.ONE_DANK_REGEX"/>

DEMO

Answer 3

Answer №2

Enum can only hold strings and numbers as values.

If you need to store regular expressions, utilize a static class for that purpose.

export class RegularExpression
{
    public static ALPHA_CHARACTERS: RegExp = /([^A-Za-z])+/g;
}

Example of Usage:

'Your_* Name'.replace(RegularExpression.ALPHA_CHARACTERS, '');

Answer 4

Enum can only hold strings and numbers as values.

If you need to store regular expressions, utilize a static class for that purpose.

export class RegularExpression
{
    public static ALPHA_CHARACTERS: RegExp = /([^A-Za-z])+/g;
}

Example of Usage:

'Your_* Name'.replace(RegularExpression.ALPHA_CHARACTERS, '');

Answer 5

Answer №3

It is recommended to follow the option A provided in the accepted response and incorporate it into your code like so:

export enum Patterns {
  ONE_COOL_PATTERN = "^[cool]+$",
  FIVE_TO_TEN_FUN = "^[fun]{5,10}$",
}

public readonly patternOne = new RegExp(Patterns.ONE_COOL_PATTERN, "g");

This approach offers some flexibility when creating the regular expression object.

Answer 6

It is recommended to follow the option A provided in the accepted response and incorporate it into your code like so:

export enum Patterns {
  ONE_COOL_PATTERN = "^[cool]+$",
  FIVE_TO_TEN_FUN = "^[fun]{5,10}$",
}

public readonly patternOne = new RegExp(Patterns.ONE_COOL_PATTERN, "g");

This approach offers some flexibility when creating the regular expression object.

Angular has its own unique way of handling regular expressions through its TypeScript

Answer №1

Answer №2

Answer №3

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