fix: add typing to flag output

src/args.ts

@@ -40,4 +40,5 @@ export function newArg(arg: IArg<any>): any {
   }
 }
 
+export interface Output {[name: string]: any}
 export type Input = IArg<any>[]

src/errors.ts

@@ -7,7 +7,7 @@ import {ParserInput, ParserOutput} from './parse'
 export interface ICLIParseErrorOptions {
   parse: {
     input: ParserInput
-    output: ParserOutput
+    output: ParserOutput<any, any>
   }
 }
 

src/flags.ts

@@ -2,64 +2,76 @@ import {AlphabetLowercase, AlphabetUppercase} from './alphabet'
 
 export interface DefaultContext<T> { options: IOptionFlag<T>; flags: { [k: string]: string } }
 
-export interface IFlagBase {
+export interface IFlagBase<T, I> {
   name: string
   char?: AlphabetLowercase | AlphabetUppercase
   description?: string
   hidden?: boolean
   required?: boolean
+  parse(input: I): T
 }
 
-export interface IBooleanFlag extends IFlagBase {
+export interface IBooleanFlag<T> extends IFlagBase<T, boolean> {
   type: 'boolean'
   allowNo: boolean
 }
 
-export interface IOptionFlag<T = string> extends IFlagBase {
+export interface IOptionFlag<T> extends IFlagBase<T, string> {
   type: 'option'
   default?: T | ((context: DefaultContext<T>) => T | undefined)
   multiple: boolean
-  parse(input: string): T
+  input: string[]
 }
 
-export type Definition<T> = (options?: Partial<IOptionFlag<T>>) => IOptionFlag<T>
+export interface Definition<T> {
+  (options: {multiple: true} & Partial<IOptionFlag<T>>): IOptionFlag<T[]>
+  (options: {required: true} & Partial<IOptionFlag<T>>): IOptionFlag<T>
+  (options?: Partial<IOptionFlag<T>>): IOptionFlag<T | undefined>
+}
 
-export function option<T = string>(defaults: Partial<IOptionFlag<T>> = {}): Definition<T> {
-  return (options?: any): any => {
-    options = options || {}
+export function build<T>(defaults: {parse: IOptionFlag<T>['parse']} & Partial<IOptionFlag<T>>): Definition<T>
+export function build(defaults: Partial<IOptionFlag<string>>): Definition<string>
+export function build<T>(defaults: Partial<IOptionFlag<T>>): Definition<T> {
+  return (options: any = {}): any => {
     return {
       parse: (i: string) => i,
       ...defaults,
       ...options,
-      input: [],
+      input: [] as string[],
       multiple: !!options.multiple,
       type: 'option',
-    }
+    } as any
   }
 }
 
-export type IFlag<T> = IBooleanFlag | IOptionFlag<T>
+export type IFlag<T> = IBooleanFlag<T> | IOptionFlag<T>
 
-export function boolean(options: Partial<IBooleanFlag> = {}): IBooleanFlag {
+export function boolean<T = boolean>(options: Partial<IBooleanFlag<T>> = {}): IBooleanFlag<T> {
   return {
+    parse: b => b,
     ...options,
     allowNo: !!options.allowNo,
     type: 'boolean',
-  } as IBooleanFlag
+  } as IBooleanFlag<T>
 }
 
-export const integer = option<number>({
+export const integer = build({
   parse: input => {
     if (!/^[0-9]+$/.test(input)) throw new Error(`Expected an integer but received: ${input}`)
     return parseInt(input, 10)
   },
 })
 
-const stringFlag = option()
+export function option<T>(options: {parse: IOptionFlag<T>['parse']} & Partial<IOptionFlag<T>>) {
+  return build<T>(options)()
+}
+
+const stringFlag = build({})
 export {stringFlag as string}
 
 export const defaultFlags = {
   color: boolean({allowNo: true}),
 }
 
-export interface Input { [name: string]: IFlag<any> }
+export interface Output {[name: string]: any}
+export type Input<T extends Output> = { [P in keyof T]: IFlag<T[P]> }

src/index.ts

@@ -1,31 +1,32 @@
-export {ParserOutput, OutputArgs, OutputFlags} from './parse'
 import * as args from './args'
+import {OutputArgs, OutputFlags, ParserOutput} from './parse'
 export {args}
 import * as flags from './flags'
 export {flags}
 export {flagUsages} from './help'
 import {deps} from './deps'
-import {ParserOutput} from './parse'
 
-export interface ParserInput {
-  argv?: string[]
-  flags?: flags.Input
+export interface ParserInput<TFlags extends flags.Output> {
+  flags?: flags.Input<TFlags>
   args?: args.Input
+  argv?: string[]
   strict?: boolean
 }
 
-export function parse(options: ParserInput): ParserOutput {
+export function parse<TFlags, TArgs>(options: ParserInput<TFlags>): ParserOutput<TFlags, TArgs> {
   const input = {
-    args: (options.args || []).map(a => deps.args.newArg(a)),
+    args: (options.args || []).map((a: any) => deps.args.newArg(a as any)),
     argv: options.argv || process.argv.slice(2),
     flags: {
       color: deps.flags.defaultFlags.color,
-      ...((options.flags || {})),
+      ...((options.flags || {})) as any,
     },
     strict: options.strict !== false,
   }
   const parser = new deps.parse.Parser(input)
   const output = parser.parse()
   deps.validate.validate({input, output})
-  return output
+  return output as any
 }
+
+export {OutputFlags, OutputArgs, ParserOutput}

src/parse.ts

@@ -15,11 +15,11 @@ try {
   debug = () => {}
 }
 
-export interface OutputArgs { [k: string]: any }
-export interface OutputFlags { [k: string]: any }
-export interface ParserOutput {
-  flags: OutputFlags
-  args: { [k: string]: any }
+export type OutputArgs<T extends ParserInput['args']> = { [P in keyof T]: any }
+export type OutputFlags<T extends ParserInput['flags']> = { [P in keyof T]: any }
+export interface ParserOutput<TFlags extends OutputFlags<any>, TArgs extends OutputArgs<any>> {
+  flags: TFlags
+  args: TArgs
   argv: string[]
   raw: ParsingToken[]
 }
@@ -30,16 +30,16 @@ export type ParsingToken = ArgToken | FlagToken
 
 export interface ParserInput {
   argv: string[]
-  flags: Flags.Input
+  flags: Flags.Input<any>
   args: Arg<any>[]
   strict: boolean
 }
 
-export class Parser {
+export class Parser<T extends ParserInput, TFlags extends OutputFlags<T['flags']>, TArgs extends OutputArgs<T['args']>> {
   private readonly argv: string[]
   private readonly raw: ParsingToken[] = []
-  private readonly booleanFlags: { [k: string]: Flags.IBooleanFlag }
-  constructor(readonly input: ParserInput) {
+  private readonly booleanFlags: { [k: string]: Flags.IBooleanFlag<any> }
+  constructor(readonly input: T) {
     this.argv = input.argv.slice(0)
     this._setNames()
     this.booleanFlags = _.pickBy(input.flags, f => f.type === 'boolean') as any
@@ -132,17 +132,17 @@ export class Parser {
     }
   }
 
-  private _args(argv: any[]): OutputArgs {
-    const args: OutputArgs = {}
+  private _args(argv: any[]): TArgs {
+    const args = {} as any
     for (let i = 0; i < this.input.args.length; i++) {
       const arg = this.input.args[i]
       args[arg.name!] = argv[i]
     }
     return args
   }
 
-  private _flags(): OutputFlags {
-    const flags: OutputFlags = {}
+  private _flags(): TFlags {
+    const flags = {} as any
     for (const token of this._flagTokens) {
       const flag = this.input.flags[token.flag]
       if (!flag) throw new Error(`Unexpected flag ${token.flag}`)

src/validate.ts

@@ -1,7 +1,7 @@
 import {deps} from './deps'
 import {ParserInput, ParserOutput} from './parse'
 
-export function validate(parse: { input: ParserInput; output: ParserOutput }) {
+export function validate(parse: { input: ParserInput; output: ParserOutput<any, any> }) {
   function validateArgs() {
     const maxArgs = parse.input.args.length
     if (parse.input.strict && parse.output.argv.length > maxArgs) {

test/parse.test.ts

@@ -208,13 +208,15 @@ See more help with --help`)
     describe('multiple flags', () => {
       it('parses multiple flags', () => {
         const out = parse({
-          argv: ['--bar', 'a', '--bar=b', '--foo=c'],
+          argv: ['--bar', 'a', '--bar=b', '--foo=c', '--baz=d'],
           flags: {
-            bar: flags.string({multiple: true}),
             foo: flags.string(),
+            bar: flags.string({multiple: true}),
+            baz: flags.string({required: true}),
           },
         })
-        expect(out.flags.foo.toUpperCase()).to.equal('C')
+        expect(out.flags.foo!.toUpperCase()).to.equal('C')
+        expect(out.flags.baz.toUpperCase()).to.equal('D')
         expect(out.flags.bar.join('|')).to.equal('a|b')
       })
     })
@@ -341,8 +343,27 @@ See more help with --help`)
   })
 
   describe('custom option', () => {
+    it('can pass parse fn', () => {
+      const foo = flags.option({char: 'f', parse: () => 100})
+      const out = parse({
+        argv: ['-f', 'bar'],
+        flags: {foo},
+      })
+      expect(out.flags).to.deep.include({foo: 100})
+    })
+  })
+
+  describe('build', () => {
+    it('can pass parse fn', () => {
+      const foo = flags.build({char: 'f', parse: () => 100})
+      const out = parse({
+        argv: ['-f', 'bar'],
+        flags: {foo: foo()},
+      })
+      expect(out.flags).to.deep.include({foo: 100})
+    })
     it('does not require parse fn', () => {
-      const foo = flags.option({char: 'f'})
+      const foo = flags.build({char: 'f'})
       const out = parse({
         argv: ['-f', 'bar'],
         flags: {foo: foo()},