extract-exclude-template-literal.md

Extract and Exclude with Template Literals

Match Strings Starting/Ending with a Substring

• starting with a

type Matches = Extract<
  'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
  `a${string}`
>;

// 'animal' | 'anaconda'

• ending with a

type Matches = Extract<
	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
	`${string}a`
>;

// 'giraffa' | 'anaconda'

• starting and ending with a

type Matches = Extract<
	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
	`a${string}a`
>;

// 'anaconda'

• starting or ending with a

type Matches = Extract<
	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
	`a${string}` | `${string}a`
>;

// 'giraffa' | 'animal' | 'anaconda'

Match Strings Containing a Substring

• containing a

type Matches = Extract<
	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
	`${string}a${string}`
>;

// 'cat' | 'giraffa' | 'animal' | 'anaconda'

• containing a everywhere but start and end

type Matches = Exclude<
	Extract<
		'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
		`${string}a${string}`
	>,
	`a${string}` | `${string}a`
>;

// 'cat'

Negative Matches

• not starting with a, b, c

type Matches = Exclude<
	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
	`${'a' | 'b' | 'c'}${string}`
>;

// 'dog' | 'giraffa'

• not ending with a, g

type Matches = Exclude<
  'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
  `${string}${'a' | 'g'}`
>;

// 'cat' | 'animal'

• not containing i, d

type Matches = Exclude<
  'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda',
  `${string}${'i' | 'd'}${string}`
>;

// 'cat'

Occurencies

• containing at least 3 times a

type Matches = Extract<
	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda' | 'nananana' | 'xaaxaaxx',
	`${string}a${string}a${string}a${string}`
>;

// 'anaconda' | 'nananana' | 'xaaxaaxx'

• containing at most 3 times a

type Matches = Extract<
  Exclude<
  	'cat' | 'dog' | 'giraffa' | 'animal' | 'anaconda' | 'nananana' | 'xaaxaaxx',
  	`${string}a${string}a${string}a${string}a${string}`
  >,
  `${string}a${string}`
>;

// 'cat' | 'giraffa' | 'animal' | 'anaconda'