Merge pull request DefinitelyTyped#32067 from YashdalfTheGray/master

@types/yup: Add a ValidationError class to match the source code

types/yup/index.d.ts

@@ -8,7 +8,7 @@
 //                 Vincent Pizzo <https://github.com/vincentjames501>
 //                 Robert Bullen <https://github.com/robertbullen>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.2
+// TypeScript Version: 2.8
 
 export function reach<T>(
     schema: Schema<T>,
@@ -23,12 +23,6 @@ export function addMethod<T extends Schema<any>>(
 ): void;
 export function ref(path: string, options?: { contextPrefix: string }): Ref;
 export function lazy<T>(fn: (value: T) => Schema<T>): Lazy;
-export function ValidationError(
-    errors: string | string[],
-    value: any,
-    path: string,
-    type?: any
-): ValidationError;
 export function setLocale(customLocale: LocaleObject): void;
 
 export const mixed: MixedSchemaConstructor;
@@ -49,7 +43,8 @@ export type AnySchemaConstructor =
     | ArraySchemaConstructor
     | ObjectSchemaConstructor;
 
-export type TestOptionsMessage = string
+export type TestOptionsMessage =
+    | string
     | ((params: object & Partial<TestMessageParams>) => string);
 
 export interface Schema<T> {
@@ -171,14 +166,19 @@ export interface ArraySchema<T> extends Schema<T[]> {
     compact(rejector?: (value: any) => boolean): ArraySchema<T>;
 }
 
-export type ObjectSchemaDefinition<T extends object> = { [field in keyof T]: Schema<T[field]> | Ref };
+export type ObjectSchemaDefinition<T extends object> = {
+    [field in keyof T]: Schema<T[field]> | Ref
+};
 
 /**
  * Merges two interfaces. For properties in common, property types from `U` trump those of `T`.
  * This is conducive to the functionality of
  * [yup's `object.shape()` method](https://www.npmjs.com/package/yup#objectshapefields-object-nosortedges-arraystring-string-schema).
  */
-export type Shape<T extends object, U extends object> = { [P in keyof T]: P extends keyof U ? U[P] : T[P] } & U;
+export type Shape<T extends object, U extends object> = {
+    [P in keyof T]: P extends keyof U ? U[P] : T[P]
+} &
+    U;
 
 export interface ObjectSchemaConstructor {
     <T extends object>(fields?: ObjectSchemaDefinition<T>): ObjectSchema<T>;
@@ -191,7 +191,10 @@ export interface ObjectSchema<T extends object> extends Schema<T> {
         noSortEdges?: Array<[string, string]>
     ): ObjectSchema<Shape<T, U>>;
     from(fromKey: string, toKey: string, alias?: boolean): ObjectSchema<T>;
-    noUnknown(onlyKnownKeys?: boolean, message?: TestOptionsMessage): ObjectSchema<T>;
+    noUnknown(
+        onlyKnownKeys?: boolean,
+        message?: TestOptionsMessage
+    ): ObjectSchema<T>;
     transformKeys(callback: (key: any) => any): void;
     camelCase(): ObjectSchema<T>;
     constantCase(): ObjectSchema<T>;
@@ -292,7 +295,12 @@ export interface SchemaDescription {
     fields: object;
 }
 
-export interface ValidationError {
+// ValidationError works a lot more like a class vs. a constructor
+// function that returns an interface. It's also got a couple of
+// static methods and it inherits from the generic Error class in
+// the [yup codebase][1].
+// [1]: (https://github.com/jquense/yup/blob/master/src/ValidationError.js)
+export class ValidationError extends Error {
     name: string;
     message: string;
     value: any;
@@ -311,6 +319,19 @@ export interface ValidationError {
      */
     inner: ValidationError[];
     params?: object;
+
+    static isError(err: any): err is ValidationError;
+    static formatError(
+        message: string | ((params?: any) => string),
+        params?: any
+    ): string | ((params?: any) => string);
+
+    constructor(
+        errors: string | string[],
+        value: any,
+        path: string,
+        type?: any
+    );
 }
 
 // It is tempting to declare `Ref` very simply, but there are problems with these approaches:

types/yup/yup-tests.ts

@@ -77,12 +77,21 @@ const renderable = yup.lazy(value => {
 });
 const renderables = yup.array().of(renderable);
 
+// ValidationError static methods
+// $ExpectType boolean
+ValidationError.isError(new ValidationError("error", "value", "path"));
+// $ExpectType string | ((params?: any) => string)
+ValidationError.formatError("error", { path: "path" });
+ValidationError.formatError("error");
+ValidationError.formatError(() => "error");
+ValidationError.formatError(() => "error", { path: "path" });
+
 // ValidationError
-let error: ValidationError = yup.ValidationError("error", "value", "path");
-error = yup.ValidationError(["error", "error2"], true, "path");
-error = yup.ValidationError(["error", "error2"], 5, "path");
-error = yup.ValidationError(["error", "error2"], { name: "value" }, "path");
-error = yup.ValidationError(
+let error: ValidationError = new yup.ValidationError("error", "value", "path");
+error = new yup.ValidationError(["error", "error2"], true, "path");
+error = new yup.ValidationError(["error", "error2"], 5, "path");
+error = new yup.ValidationError(["error", "error2"], { name: "value" }, "path");
+error = new yup.ValidationError(
     ["error", "error2"],
     { name: "value" },
     "path",
@@ -93,7 +102,7 @@ error = {
     message: "error",
     path: "path",
     errors: ["error"],
-    inner: [yup.ValidationError("error", true, "path")],
+    inner: [new yup.ValidationError("error", true, "path")],
     type: "date",
     value: { start: "2017-11-10" }
 };
@@ -135,8 +144,8 @@ mixed.default(() => ({ number: 5 }));
 mixed.default();
 mixed.nullable(true);
 mixed.required();
-mixed.required('Foo');
-mixed.required(() => 'Foo');
+mixed.required("Foo");
+mixed.required(() => "Foo");
 mixed.notRequired(); // $ExpectType MixedSchema
 mixed.typeError("type error");
 mixed.typeError(() => "type error");
@@ -155,10 +164,8 @@ mixed
         then: yup.number().min(5),
         otherwise: yup.number().min(0)
     })
-    .when(
-        "$other",
-        (value: any, schema: MixedSchema) =>
-            value === 4 ? schema.required() : schema
+    .when("$other", (value: any, schema: MixedSchema) =>
+        value === 4 ? schema.required() : schema
     );
 // tslint:disable-next-line:no-invalid-template-strings
 mixed.test("is-jimmy", "${path} is not Jimmy", value => value === "jimmy");
@@ -486,8 +493,8 @@ interface ExpectedABC {
 }
 
 const expectedAbc: ExpectedABC = {
-    a: 'qwerty',
-    b: 'asdfg',
+    a: "qwerty",
+    b: "asdfg",
     c: 123
 };
 const actualAbc: yup.Shape<AB, BC> = expectedAbc;