1 import {UpperCaseCharacters, WordSeparators} from '../source/utilities';
4 Unlike a simpler split, this one includes the delimiter splitted on in the resulting array literal. This is to enable splitting on, for example, upper-case characters.
6 export type SplitIncludingDelimiters<Source extends string, Delimiter extends string> =
7 Source extends '' ? [] :
8 Source extends `${infer FirstPart}${Delimiter}${infer SecondPart}` ?
10 Source extends `${FirstPart}${infer UsedDelimiter}${SecondPart}`
11 ? UsedDelimiter extends Delimiter
12 ? Source extends `${infer FirstPart}${UsedDelimiter}${infer SecondPart}`
13 ? [...SplitIncludingDelimiters<FirstPart, Delimiter>, UsedDelimiter, ...SplitIncludingDelimiters<SecondPart, Delimiter>]
21 Format a specific part of the splitted string literal that `StringArrayToDelimiterCase<>` fuses together, ensuring desired casing.
23 @see StringArrayToDelimiterCase
25 type StringPartToDelimiterCase<StringPart extends string, UsedWordSeparators extends string, UsedUpperCaseCharacters extends string, Delimiter extends string> =
26 StringPart extends UsedWordSeparators ? Delimiter :
27 StringPart extends UsedUpperCaseCharacters ? `${Delimiter}${Lowercase<StringPart>}` :
31 Takes the result of a splitted string literal and recursively concatenates it together into the desired casing.
33 It receives `UsedWordSeparators` and `UsedUpperCaseCharacters` as input to ensure it's fully encapsulated.
35 @see SplitIncludingDelimiters
37 type StringArrayToDelimiterCase<Parts extends any[], UsedWordSeparators extends string, UsedUpperCaseCharacters extends string, Delimiter extends string> =
38 Parts extends [`${infer FirstPart}`, ...infer RemainingParts]
39 ? `${StringPartToDelimiterCase<FirstPart, UsedWordSeparators, UsedUpperCaseCharacters, Delimiter>}${StringArrayToDelimiterCase<RemainingParts, UsedWordSeparators, UsedUpperCaseCharacters, Delimiter>}`
43 Convert a string literal to a custom string delimiter casing.
45 This can be useful when, for example, converting a camel-cased object property to an oddly cased one.
52 import {DelimiterCase} from 'type-fest';
56 const someVariable: DelimiterCase<'fooBar', '#'> = 'foo#bar';
60 type OddlyCasedProps<T> = {
61 [K in keyof T as DelimiterCase<K, '#'>]: T[K]
64 interface SomeOptions {
70 const rawCliOptions: OddlyCasedProps<SomeOptions> = {
72 'include#file': 'bar.js',
78 export type DelimiterCase<Value, Delimiter extends string> = Value extends string
79 ? StringArrayToDelimiterCase<
80 SplitIncludingDelimiters<Value, WordSeparators | UpperCaseCharacters>,