import {WordSeparators} from '../source/utilities';
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/**
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Recursively split a string literal into two parts on the first occurence of the given string, returning an array literal of all the separate parts.
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*/
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export type Split<S extends string, D extends string> =
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string extends S ? string[] :
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S extends '' ? [] :
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S extends `${infer T}${D}${infer U}` ? [T, ...Split<U, D>] :
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[S];
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/**
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Step by step takes the first item in an array literal, formats it and adds it to a string literal, and then recursively appends the remainder.
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Only to be used by `CamelCaseStringArray<>`.
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@see CamelCaseStringArray
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*/
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type InnerCamelCaseStringArray<Parts extends any[], PreviousPart> =
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Parts extends [`${infer FirstPart}`, ...infer RemainingParts]
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? FirstPart extends undefined
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? ''
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: FirstPart extends ''
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? InnerCamelCaseStringArray<RemainingParts, PreviousPart>
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: `${PreviousPart extends '' ? FirstPart : Capitalize<FirstPart>}${InnerCamelCaseStringArray<RemainingParts, FirstPart>}`
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: '';
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/**
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Starts fusing the output of `Split<>`, an array literal of strings, into a camel-cased string literal.
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It's separate from `InnerCamelCaseStringArray<>` to keep a clean API outwards to the rest of the code.
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@see Split
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*/
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type CamelCaseStringArray<Parts extends string[]> =
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Parts extends [`${infer FirstPart}`, ...infer RemainingParts]
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? Uncapitalize<`${FirstPart}${InnerCamelCaseStringArray<RemainingParts, FirstPart>}`>
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: never;
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/**
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Convert a string literal to camel-case.
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This can be useful when, for example, converting some kebab-cased command-line flags or a snake-cased database result.
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@example
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```
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import {CamelCase} from 'type-fest';
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// Simple
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const someVariable: CamelCase<'foo-bar'> = 'fooBar';
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// Advanced
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type CamelCasedProps<T> = {
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[K in keyof T as CamelCase<K>]: T[K]
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};
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interface RawOptions {
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'dry-run': boolean;
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'full_family_name': string;
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foo: number;
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}
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const dbResult: CamelCasedProps<ModelProps> = {
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dryRun: true,
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fullFamilyName: 'bar.js',
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foo: 123
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};
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```
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*/
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export type CamelCase<K> = K extends string ? CamelCaseStringArray<Split<K, WordSeparators>> : K;
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