fix(flags): print formatted error message for boolean and number vali…

…dation errors (#189)

flags/_errors.ts

@@ -1,5 +1,5 @@
 import { didYouMeanOption, didYouMeanType, getFlag } from "./_utils.ts";
-import type { IFlagOptions } from "./types.ts";
+import type { IFlagOptions, ITypeInfo } from "./types.ts";
 
 export class FlagsError extends Error {
   constructor(message: string) {
@@ -148,3 +148,17 @@ export class NoArguments extends ValidationError {
     Object.setPrototypeOf(this, NoArguments.prototype);
   }
 }
+
+export class InvalidTypeError extends ValidationError {
+  constructor(
+    { label, name, value, type }: ITypeInfo,
+    expected?: Array<string>,
+  ) {
+    super(
+      `${label} "${name}" must be of type "${type}", but got "${value}".` + (
+        expected ? ` Expected values: ${expected.join(", ")}` : ""
+      ),
+    );
+    Object.setPrototypeOf(this, MissingOptionValue.prototype);
+  }
+}

flags/types/boolean.ts

@@ -1,18 +1,17 @@
 import type { ITypeHandler, ITypeInfo } from "../types.ts";
+import { InvalidTypeError } from "../_errors.ts";
 
 /** Boolean type handler. Excepts `true`, `false`, `1`, `0` */
 export const boolean: ITypeHandler<boolean> = (
-  { label, name, value, type }: ITypeInfo,
+  type: ITypeInfo,
 ): boolean => {
-  if (~["1", "true"].indexOf(value)) {
+  if (~["1", "true"].indexOf(type.value)) {
     return true;
   }
 
-  if (~["0", "false"].indexOf(value)) {
+  if (~["0", "false"].indexOf(type.value)) {
     return false;
   }
 
-  throw new Error(
-    `${label} "${name}" must be of type "${type}", but got "${value}".`,
-  );
+  throw new InvalidTypeError(type);
 };

flags/types/number.ts

@@ -1,14 +1,11 @@
 import type { ITypeHandler, ITypeInfo } from "../types.ts";
+import { InvalidTypeError } from "../_errors.ts";
 
 /** Number type handler. Excepts any numeric value. */
-export const number: ITypeHandler<number> = (
-  { label, name, value, type }: ITypeInfo,
-): number => {
-  if (isNaN(Number(value))) {
-    throw new Error(
-      `${label} "${name}" must be of type "${type}", but got "${value}".`,
-    );
+export const number: ITypeHandler<number> = (type: ITypeInfo): number => {
+  if (!isNaN(Number(type.value))) {
+    return parseFloat(type.value);
   }
 
-  return parseFloat(value);
+  throw new InvalidTypeError(type);
 };

pagic.config.tsx

@@ -1,4 +1,3 @@
-// deno-lint-ignore no-unused-vars
 import { React } from "https://deno.land/x/pagic/mod.ts";
 
 export default {