make splice deleteCount required in es5.d.ts

In ES5 `deleteCount` is not an optional argument. If it is not provided it defaults to 0 as a side effect of `undefined` being converted to an integer.

In ES6 `deleleteCount` is optional, and it defaults to the length of the array minus the start index.

If you are targeting ES5 but don't provide `deleteCount` the behaviour will be different depending on the environment your build is running in.

fixes microsoft#32638

src/lib/es2015.core.d.ts

@@ -42,6 +42,15 @@ interface Array<T> {
      * @param end If not specified, length of the this object is used as its default value.
      */
     copyWithin(target: number, start: number, end?: number): this;
+
+    /**
+     * Removes elements from an array and, if necessary, inserts new elements in their place, returning the deleted elements.
+     * @param start The zero-based location in the array from which to start removing elements.
+     * @param deleteCount The number of elements to remove. If deleteCount is omitted, or if its value is equal to or larger
+     * than array.length - start (that is, if it is equal to or greater than the number of elements left in the array,
+     * starting at start), then all the elements from start to the end of the array will be deleted.
+     */
+    splice(start: number, deleteCount?: number): T[];
 }
 
 interface ArrayConstructor {

src/lib/es5.d.ts

@@ -1243,7 +1243,7 @@ interface Array<T> {
       * @param start The zero-based location in the array from which to start removing elements.
       * @param deleteCount The number of elements to remove.
       */
-    splice(start: number, deleteCount?: number): T[];
+    splice(start: number, deleteCount: number): T[];
     /**
       * Removes elements from an array and, if necessary, inserts new elements in their place, returning the deleted elements.
       * @param start The zero-based location in the array from which to start removing elements.

tests/baselines/reference/arraySlice.types

@@ -4,9 +4,9 @@ var arr: string[] | number[];
 
 arr.splice(1, 1);
 >arr.splice(1, 1) : string[] | number[]
->arr.splice : { (start: number, deleteCount?: number): string[]; (start: number, deleteCount: number, ...items: string[]): string[]; } | { (start: number, deleteCount?: number): number[]; (start: number, deleteCount: number, ...items: number[]): number[]; }
+>arr.splice : { (start: number, deleteCount: number): string[]; (start: number, deleteCount: number, ...items: string[]): string[]; } | { (start: number, deleteCount: number): number[]; (start: number, deleteCount: number, ...items: number[]): number[]; }
 >arr : string[] | number[]
->splice : { (start: number, deleteCount?: number): string[]; (start: number, deleteCount: number, ...items: string[]): string[]; } | { (start: number, deleteCount?: number): number[]; (start: number, deleteCount: number, ...items: number[]): number[]; }
+>splice : { (start: number, deleteCount: number): string[]; (start: number, deleteCount: number, ...items: string[]): string[]; } | { (start: number, deleteCount: number): number[]; (start: number, deleteCount: number, ...items: number[]): number[]; }
 >1 : 1
 >1 : 1
 

tests/baselines/reference/invalidSplice.types

@@ -2,9 +2,9 @@
 var arr = [].splice(0,3,4,5);
 >arr : any[]
 >[].splice(0,3,4,5) : any[]
->[].splice : { (start: number, deleteCount?: number): any[]; (start: number, deleteCount: number, ...items: any[]): any[]; }
+>[].splice : { (start: number, deleteCount: number): any[]; (start: number, deleteCount: number, ...items: any[]): any[]; }
 >[] : undefined[]
->splice : { (start: number, deleteCount?: number): any[]; (start: number, deleteCount: number, ...items: any[]): any[]; }
+>splice : { (start: number, deleteCount: number): any[]; (start: number, deleteCount: number, ...items: any[]): any[]; }
 >0 : 0
 >3 : 3
 >4 : 4

tests/baselines/reference/parserharness.types

@@ -6383,11 +6383,11 @@ module Harness {
 
                 this.editRanges.splice(0, this.maxScriptVersions - this.editRanges.length);
 >this.editRanges.splice(0, this.maxScriptVersions - this.editRanges.length) : { length: number; editRange: any; }[]
->this.editRanges.splice : { (start: number, deleteCount?: number): { length: number; editRange: any; }[]; (start: number, deleteCount: number, ...items: { length: number; editRange: any; }[]): { length: number; editRange: any; }[]; }
+>this.editRanges.splice : { (start: number, deleteCount: number): { length: number; editRange: any; }[]; (start: number, deleteCount: number, ...items: { length: number; editRange: any; }[]): { length: number; editRange: any; }[]; }
 >this.editRanges : { length: number; editRange: any; }[]
 >this : this
 >editRanges : { length: number; editRange: any; }[]
->splice : { (start: number, deleteCount?: number): { length: number; editRange: any; }[]; (start: number, deleteCount: number, ...items: { length: number; editRange: any; }[]): { length: number; editRange: any; }[]; }
+>splice : { (start: number, deleteCount: number): { length: number; editRange: any; }[]; (start: number, deleteCount: number, ...items: { length: number; editRange: any; }[]): { length: number; editRange: any; }[]; }
 >0 : 0
 >this.maxScriptVersions - this.editRanges.length : number
 >this.maxScriptVersions : number

tests/baselines/reference/restInvalidArgumentType.types

@@ -71,7 +71,7 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
 >p1 : T
 
     var {...r2} = p2;   // OK
->r2 : { [n: number]: T; length: number; toString(): string; toLocaleString(): string; pop(): T; push(...items: T[]): number; concat(...items: ConcatArray<T>[]): T[]; concat(...items: (T | ConcatArray<T>)[]): T[]; join(separator?: string): string; reverse(): T[]; shift(): T; slice(start?: number, end?: number): T[]; sort(compareFn?: (a: T, b: T) => number): T[]; splice(start: number, deleteCount?: number): T[]; splice(start: number, deleteCount: number, ...items: T[]): T[]; unshift(...items: T[]): number; indexOf(searchElement: T, fromIndex?: number): number; lastIndexOf(searchElement: T, fromIndex?: number): number; every(callbackfn: (value: T, index: number, array: T[]) => unknown, thisArg?: any): boolean; some(callbackfn: (value: T, index: number, array: T[]) => unknown, thisArg?: any): boolean; forEach(callbackfn: (value: T, index: number, array: T[]) => void, thisArg?: any): void; map<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; filter<S extends T>(callbackfn: (value: T, index: number, array: T[]) => value is S, thisArg?: any): S[]; filter(callbackfn: (value: T, index: number, array: T[]) => unknown, thisArg?: any): T[]; reduce(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T): T; reduce(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T, initialValue: T): T; reduce<U>(callbackfn: (previousValue: U, currentValue: T, currentIndex: number, array: T[]) => U, initialValue: U): U; reduceRight(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T): T; reduceRight(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T, initialValue: T): T; reduceRight<U>(callbackfn: (previousValue: U, currentValue: T, currentIndex: number, array: T[]) => U, initialValue: U): U; }
+>r2 : { [n: number]: T; length: number; toString(): string; toLocaleString(): string; pop(): T; push(...items: T[]): number; concat(...items: ConcatArray<T>[]): T[]; concat(...items: (T | ConcatArray<T>)[]): T[]; join(separator?: string): string; reverse(): T[]; shift(): T; slice(start?: number, end?: number): T[]; sort(compareFn?: (a: T, b: T) => number): T[]; splice(start: number, deleteCount: number): T[]; splice(start: number, deleteCount: number, ...items: T[]): T[]; unshift(...items: T[]): number; indexOf(searchElement: T, fromIndex?: number): number; lastIndexOf(searchElement: T, fromIndex?: number): number; every(callbackfn: (value: T, index: number, array: T[]) => unknown, thisArg?: any): boolean; some(callbackfn: (value: T, index: number, array: T[]) => unknown, thisArg?: any): boolean; forEach(callbackfn: (value: T, index: number, array: T[]) => void, thisArg?: any): void; map<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; filter<S extends T>(callbackfn: (value: T, index: number, array: T[]) => value is S, thisArg?: any): S[]; filter(callbackfn: (value: T, index: number, array: T[]) => unknown, thisArg?: any): T[]; reduce(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T): T; reduce(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T, initialValue: T): T; reduce<U>(callbackfn: (previousValue: U, currentValue: T, currentIndex: number, array: T[]) => U, initialValue: U): U; reduceRight(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T): T; reduceRight(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T, initialValue: T): T; reduceRight<U>(callbackfn: (previousValue: U, currentValue: T, currentIndex: number, array: T[]) => U, initialValue: U): U; }
 >p2 : T[]
 
     var {...r3} = t;   // Error, generic type paramter

tests/baselines/reference/restParameterWithBindingPattern3.types

@@ -31,5 +31,5 @@ function e(...{0: a = 1, 1: b = true, ...rest: rest}: [boolean, string, number])
 >b : string
 >true : true
 >rest : any
->rest : { [n: number]: string | number | boolean; 0: boolean; 1: string; 2: number; length: 3; toString(): string; toLocaleString(): string; pop(): string | number | boolean; push(...items: (string | number | boolean)[]): number; concat(...items: ConcatArray<string | number | boolean>[]): (string | number | boolean)[]; concat(...items: (string | number | boolean | ConcatArray<string | number | boolean>)[]): (string | number | boolean)[]; join(separator?: string): string; reverse(): (string | number | boolean)[]; shift(): string | number | boolean; slice(start?: number, end?: number): (string | number | boolean)[]; sort(compareFn?: (a: string | number | boolean, b: string | number | boolean) => number): [boolean, string, number]; splice(start: number, deleteCount?: number): (string | number | boolean)[]; splice(start: number, deleteCount: number, ...items: (string | number | boolean)[]): (string | number | boolean)[]; unshift(...items: (string | number | boolean)[]): number; indexOf(searchElement: string | number | boolean, fromIndex?: number): number; lastIndexOf(searchElement: string | number | boolean, fromIndex?: number): number; every(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; some(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; forEach(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => void, thisArg?: any): void; map<U>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => U, thisArg?: any): U[]; filter<S extends string | number | boolean>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => value is S, thisArg?: any): S[]; filter(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): (string | number | boolean)[]; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduce<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduceRight<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; }
+>rest : { [n: number]: string | number | boolean; 0: boolean; 1: string; 2: number; length: 3; toString(): string; toLocaleString(): string; pop(): string | number | boolean; push(...items: (string | number | boolean)[]): number; concat(...items: ConcatArray<string | number | boolean>[]): (string | number | boolean)[]; concat(...items: (string | number | boolean | ConcatArray<string | number | boolean>)[]): (string | number | boolean)[]; join(separator?: string): string; reverse(): (string | number | boolean)[]; shift(): string | number | boolean; slice(start?: number, end?: number): (string | number | boolean)[]; sort(compareFn?: (a: string | number | boolean, b: string | number | boolean) => number): [boolean, string, number]; splice(start: number, deleteCount: number): (string | number | boolean)[]; splice(start: number, deleteCount: number, ...items: (string | number | boolean)[]): (string | number | boolean)[]; unshift(...items: (string | number | boolean)[]): number; indexOf(searchElement: string | number | boolean, fromIndex?: number): number; lastIndexOf(searchElement: string | number | boolean, fromIndex?: number): number; every(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; some(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; forEach(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => void, thisArg?: any): void; map<U>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => U, thisArg?: any): U[]; filter<S extends string | number | boolean>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => value is S, thisArg?: any): S[]; filter(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): (string | number | boolean)[]; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduce<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduceRight<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; }