feat: add required option

README.md

@@ -35,7 +35,8 @@ const parsed = typeFlag(process.argv.slice(2), {
 
  someBoolean: {
  type: Boolean,
- alias: 'b'
+ alias: 'b',
+ required: true
  },
 
  // Wrap with an array to indicate an array type
@@ -46,16 +47,16 @@ const parsed = typeFlag(process.argv.slice(2), {
  }
 })
 
-console.log(parsed.flags.someString[0])
+console.log(parsed.flags.someString)
 ```
 
 `parsed` resolves to the following type:
 ```ts
 {
  flags: {
  someString: string | undefined;
- someNumber: boolean | undefined;
- someBoolean: number | undefined;
+ someNumber: number | undefined;
+ someBoolean: boolean;
  stringArray: string[];
  numberArray: number[];
  };
@@ -68,6 +69,24 @@ console.log(parsed.flags.someString[0])
 
 ### Usage
 
+#### Required flags
+Non-array types can be `undefined` unless `required: true` is set:
+```ts
+const parsed = typeFlag(process.argv.slice(2), {
+ someNumber: {
+ type: Number,
+ required: true
+ }
+})
+```
+
+When a flag is required, the return type can no longer be `undefined`:
+```ts
+{
+ someNumber: number;
+}
+```
+
 #### kebab-case flags mapped to camelCase
 When passing in the flags, they can be in kebab-case and will automatically map to the camelCase equivalent.
 ```sh
@@ -253,6 +272,7 @@ type FlagSchema = {
  [flagName: string]: TypeFunction | [TypeFunction] | {
  type: TypeFunction | [TypeFunction];
  alias?: string;
+ required?: true;
  };
 };
 ```

src/index.ts

@@ -9,6 +9,7 @@ import {
  mapAliases,
  parseFlag,
  getDefaultFromTypeWithValue,
+ validateFlags,
 } from './utils';
 
 const isAliasPattern = /^-[\da-z]+/i;
@@ -154,6 +155,8 @@ function typeFlag<Schemas extends Flags>(
  expectingValue();
  }
 
+ validateFlags(schemas, flags);
+
  return {
  flags,
  unknownFlags,

src/types.ts

@@ -5,6 +5,7 @@ export type TypeFunctionArray<T = any> = [TypeFunction<T>];
 export type FlagSchema = {
  type: TypeFunction | TypeFunctionArray;
  alias?: string;
+ required?: true;
 };
 
 export type FlagTypeOrSchema = TypeFunction | TypeFunctionArray | FlagSchema;
@@ -21,7 +22,11 @@ export type InferFlagType<
  Flag extends FlagTypeOrSchema
 > = Flag extends (TypeFunction<infer T> | { type: TypeFunction<infer T> })
  // Type function return-type
- ? (T | undefined)
+ ? (
+ Flag extends { required: true }
+ ? T
+ : T | undefined
+ )
 
  // Type function return-type in array
  : (

src/utils.ts

@@ -78,26 +78,26 @@ export function mapAliases<Schemas extends Flags>(
  schema: FlagSchema;
  }>();
 
- for (const name in schemas) {
- if (!hasOwn(schemas, name)) {
+ for (const flagName in schemas) {
+ if (!hasOwn(schemas, flagName)) {
  continue;
  }
 
- validateFlagName(schemas, name);
+ validateFlagName(schemas, flagName);
 
- const schema = schemas[name] as FlagSchema;
+ const schema = schemas[flagName] as FlagSchema;
  if (schema && typeof schema === 'object') {
  const { alias } = schema;
  if (alias) {
- assert(alias.length > 0, `Invalid flag alias ${stringify(name)}: flag alias cannot be empty`);
- assert(alias.length === 1, `Invalid flag alias ${stringify(name)}: flag aliases can only be a single-character`);
+ assert(alias.length > 0, `Invalid flag alias ${stringify(flagName)}: flag alias cannot be empty`);
+ assert(alias.length === 1, `Invalid flag alias ${stringify(flagName)}: flag aliases can only be a single-character`);
  assert(
  !aliases.has(alias),
  `Flag collision: Alias "${alias}" is already used`,
  );
 
  aliases.set(alias, {
- name,
+ name: flagName,
  schema,
  });
  }
@@ -112,10 +112,12 @@ const isArrayType = (schema: FlagTypeOrSchema) => {
  return false;
  }
 
- return (Array.isArray(schema) || Array.isArray(schema.type));
+ return Array.isArray(schema) || Array.isArray(schema.type);
 };
 
-export const createFlagsObject = <Schemas extends Flags>(schema: Flags) => {
+export const createFlagsObject = <Schemas extends Flags>(
+ schema: Schemas,
+) => {
  const flags: Record<string, any> = {};
 
  for (const flag in schema) {
@@ -143,3 +145,30 @@ export const getDefaultFromTypeWithValue = (
 
  return value;
 };
+
+export const validateFlags = <Schemas extends Flags>(
+ schemas: Schemas,
+ flags: Record<keyof Schemas, any>,
+) => {
+ for (const flagName in schemas) {
+ if (!hasOwn(schemas, flagName)) {
+ continue;
+ }
+
+ const schema = schemas[flagName];
+
+ if (
+ schema
+ && ('required' in schema)
+ && schema.required
+ ) {
+ const value = flags[flagName];
+ if (
+ value === undefined
+ || (Array.isArray(value) && value.length === 0)
+ ) {
+ throw new Error(`Missing required option "--${flagName}"`);
+ }
+ }
+ }
+};

tests/type-flag.spec.ts

@@ -148,6 +148,15 @@ describe('Parsing', () => {
  expect<string | undefined>(parsed.flags.someString).toEqual('4');
  });
 
+ test('kebab-case flags', () => {
+ const parsed = typeFlag(['--some-string=2', '--someString=3', '--some-string=4'], {
+ 'some-string': String,
+ });
+
+ expect<string | undefined>(parsed.flags['some-string']).toEqual('4');
+ expect(!('someString' in parsed.flags)).toBe(true);
+ });
+
  test('flag=', () => {
  const parsed = typeFlag(['--string=hello', '-s=bye', '--string=', '--boolean=true', '--boolean=false', '--boolean=', 'world', '--number=3.14', '--number='], {
  string: {
@@ -293,4 +302,44 @@ describe('Parsing', () => {
  expect<number[]>(parsed.flags.numberArray).toEqual([1, 2]);
  expect<string[]>(parsed._).toEqual(['world']);
  });
+
+ describe('Required flag', () => {
+ test('Types and parsing', () => {
+ const parsed = typeFlag(['--string', 'hello', '--boolean', '--number', '1'], {
+ string: {
+ type: String,
+ required: true,
+ },
+ boolean: {
+ type: Boolean,
+ required: true,
+ },
+ number: Number,
+ });
+
+ expect<string>(parsed.flags.string).toEqual('hello');
+ expect<boolean>(parsed.flags.boolean).toEqual(true);
+ expect<number | undefined>(parsed.flags.number).toEqual(1);
+ });
+
+ test('Throw on missing', () => {
+ expect(() => {
+ typeFlag([], {
+ flagA: {
+ type: String,
+ required: true,
+ },
+ });
+ }).toThrow(/* 'Missing required option "--flagA"' */);
+
+ expect(() => {
+ typeFlag([], {
+ flagA: {
+ type: [String],
+ required: true,
+ },
+ });
+ }).toThrow(/* 'Missing required option "--flagA"' */);
+ });
+ });
 });