feat(core): will now coerce values to correct type

BREAKING CHANGE: execute function no longer returns a promise

Author: codeandcats

package-lock.json

@@ -64,6 +64,7 @@
     "typescript": "^3.0.3"
   },
   "dependencies": {
+    "boolean": "^0.2.0",
     "chalk": "^2.4.1",
     "commander": "^2.18.0",
     "fs-extra": "^7.0.0",

package.json

@@ -0,0 +1,20 @@
+import { coerceValue } from './coercion';
+
+describe('src/coercion', () => {
+  describe('coerceValue', () => {
+    it('should coerce strings to strings', () => {
+      expect(coerceValue('123', String)).toStrictEqual('123');
+    });
+
+    it('should coerce strings to strings', () => {
+      expect(coerceValue('123', Number)).toStrictEqual(123);
+      expect(coerceValue('123', Number)).not.toStrictEqual('123');
+    });
+
+    it('should coerce strings to strings', () => {
+      expect(coerceValue('true', Boolean)).toStrictEqual(true);
+      expect(coerceValue('123', Boolean)).not.toStrictEqual('123');
+      expect(coerceValue('123', Boolean)).not.toStrictEqual(123);
+    });
+  });
+});

src/coercion.test.ts

@@ -0,0 +1,18 @@
+import * as parseBoolean from 'boolean';
+
+export function coerceValue(value: string, toType: typeof String): string;
+export function coerceValue(value: string, toType: typeof Number): number;
+export function coerceValue(value: string, toType: typeof Boolean): boolean;
+
+export function coerceValue(
+  value: string,
+  toType: typeof String | typeof Number | typeof Boolean,
+): string | number | boolean {
+  if (toType === Number) {
+    return +value;
+  } else if (toType === Boolean) {
+    return parseBoolean(value);
+  } else {
+    return value;
+  }
+}

src/coercion.ts

@@ -1,5 +1,6 @@
 import chalk from 'chalk';
 import * as cli from 'commander';
+import { coerceValue } from './coercion';
 import { errorToString } from './errors';
 import { getCommandOptions, getCommandValues } from './metadata';
 import { Command, CommandClass, CommandDefinition, CommandOptionDefinition, IocContainer } from './types';
@@ -39,11 +40,14 @@ function getParams(
   const values = getCommandValues(command.paramsClass.prototype);
   const options = getCommandOptions(command.paramsClass.prototype);
 
-  const params: { [paramName: string]: any } = new command.paramsClass();
+  const params: { [paramName: string]: string | number | boolean } = new command.paramsClass();
   let paramIndex = 0;
 
   for (const value of values) {
-    params[value.name] = args[paramIndex++];
+    params[value.name] = coerceValue(
+      args[paramIndex++],
+      value.type as any // Not sure why TS complains here without cast to any 🤔
+    );
   }
 
   const optionValues = args[paramIndex];
@@ -67,7 +71,7 @@ function registerCommandOption(
   option: CommandOptionDefinition
 ) {
   const optionUsage = getOptionUsage(option);
-  const coerceValue = !option.valueName ? undefined : ((value: string) => {
+  const coercedValue = !option.valueName ? undefined : ((value: string) => {
     if (option.valueName && option.type === Number) {
       return +value;
     } else {
@@ -81,7 +85,7 @@ function registerCommandOption(
   cliCommand.option(
     optionUsage,
     option.description,
-    coerceValue,
+    coercedValue,
     defaultValue
   );
 }

src/commander.ts

@@ -28,7 +28,7 @@ export async function commandsFromDirectory(directoryPath: string): Promise<Comm
   return commander.commandsFromDirectory(directoryPath);
 }
 
-export async function execute(argv?: string[]): Promise<void> {
+export function execute(argv?: string[]) {
   return commander.execute(argv);
 }