Merge pull request #30201 from drewwyatt/master

[ramda] Adds Placeholder (R.__) support

types/ramda/index.d.ts

@@ -1,4 +1,4 @@
-// Type definitions for ramda 0.25
+// Type definitions for ramda 0.26
 // Project: https://github.com/donnut/typescript-ramda
 // Definitions by: Erwin Poeze <https://github.com/donnut>
 //                 Tycho Grouwstra <https://github.com/tycho01>
@@ -23,6 +23,7 @@
 //                 Marcin Biernat <https://github.com/biern>
 //                 Rayhaneh Banyassady <https://github.com/rayhaneh>
 //                 Ryan McCuaig <https://github.com/rgm>
+//                 Drew Wyatt <https://github.com/drewwyatt>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.8
 
@@ -430,12 +431,20 @@ declare namespace R {
         (t1: T1, t2: T2, t3: T3, t4: T4, t5: T5, t6: T6): R;
     }
 
+    interface Placeholder { __isRamdaPlaceholder__: true; }
+
     interface Reduced<T> {
         '@@transducer/value': T;
         '@@transducer/reduced': true;
     }
 
     interface Static {
+        /**
+         * Placeholder. When used with functions like curry, or op, the second argument is applied to the second
+         * position, and it returns a function waiting for its first argument.
+         */
+        __: Placeholder; /* This is used in examples throughout the docs, but I it only seems to be directly explained here: https://ramdajs.com/0.9/docs/#op */
+
         /**
          * Adds two numbers (or strings). Equivalent to a + b but curried.
          */
@@ -754,6 +763,8 @@ declare namespace R {
          * Returns a new list consisting of the elements of the first list followed by the elements
          * of the second.
          */
+        concat<T>(placeholder: Placeholder): (list2: ReadonlyArray<T>, list1: ReadonlyArray<T>) => T[];
+        concat<T>(placeholder: Placeholder, list2: ReadonlyArray<T>): (list1: ReadonlyArray<T>) => T[];
         concat<T>(list1: ReadonlyArray<T>, list2: ReadonlyArray<T>): T[];
         concat<T>(list1: ReadonlyArray<T>): (list2: ReadonlyArray<T>) => T[];
         concat(list1: string, list2: string): string;
@@ -782,6 +793,10 @@ declare namespace R {
          * Returns `true` if the specified item is somewhere in the list, `false` otherwise.
          * Equivalent to `indexOf(a)(list) > -1`. Uses strict (`===`) equality checking.
          */
+        contains(__: Placeholder, list: string): (a: string) => boolean;
+        contains<T>(__: Placeholder, list: T[]): (a: T) => boolean;
+        contains(__: Placeholder): (list: string, a: string) => boolean;
+        contains<T>(__: Placeholder): (list: T[], a: T) => boolean;
         contains(a: string, list: string): boolean;
         contains<T>(a: T, list: ReadonlyArray<T>): boolean;
         contains(a: string): (list: string) => boolean;
@@ -876,6 +891,8 @@ declare namespace R {
         /**
          * Divides two numbers. Equivalent to a / b.
          */
+        divide(__: Placeholder, b: number): (a: number) => number;
+        divide(__: Placeholder): (b: number, a: number) => number;
         divide(a: number, b: number): number;
         divide(a: number): (b: number) => number;
 
@@ -1053,18 +1070,24 @@ declare namespace R {
         /**
          * Returns true if the first parameter is greater than the second.
          */
+        gt(__: Placeholder, b: number): (a: number) => boolean;
+        gt(__: Placeholder): (b: number, a: number) => boolean;
         gt(a: number, b: number): boolean;
         gt(a: number): (b: number) => boolean;
 
         /**
          * Returns true if the first parameter is greater than or equal to the second.
          */
+        gte(__: Placeholder, b: number): (a: number) => boolean;
+        gte(__: Placeholder): (b: number, a: number) => boolean;
         gte(a: number, b: number): boolean;
         gte(a: number): (b: number) => boolean;
 
         /**
          * Returns whether or not an object has an own property with the specified name.
          */
+        has<T>(__: Placeholder, obj: T): (s: string) => boolean;
+        has<T>(__: Placeholder): (obj: T, s: string) => boolean;
         has<T>(s: string, obj: T): boolean;
         has(s: string): <T>(obj: T) => boolean;
 
@@ -1300,12 +1323,16 @@ declare namespace R {
         /**
          * Returns true if the first parameter is less than the second.
          */
+        lt(__: Placeholder, b: number): (a: number) => boolean;
+        lt(__: Placeholder): (b: number, a: number) => boolean;
         lt(a: number, b: number): boolean;
         lt(a: number): (b: number) => boolean;
 
         /**
          * Returns true if the first parameter is less than or equal to the second.
          */
+        lte(__: Placeholder, b: number): (a: number) => boolean;
+        lte(__: Placeholder): (b: number, a: number) => boolean;
         lte(a: number, b: number): boolean;
         lte(a: number): (b: number) => boolean;
 
@@ -1361,6 +1388,8 @@ declare namespace R {
          * mathMod(-17, 5) is 3. mathMod requires Integer arguments, and returns NaN
          * when the modulus is zero or negative.
          */
+        mathMod(__: Placeholder, b: number): (a: number) => number;
+        mathMod(__: Placeholder): (b: number, a: number) => number;
         mathMod(a: number, b: number): number;
         mathMod(a: number): (b: number) => number;
 
@@ -1409,6 +1438,8 @@ declare namespace R {
          * merged with the own properties of object b.
          * This function will *not* mutate passed-in objects.
          */
+        merge<T2>(__: Placeholder, b: T2): <T1>(a: T1) => T1 & T2;
+        merge(__: Placeholder): <T1, T2>(b: T2, a: T1) => T1 & T2;
         merge<T1, T2>(a: T1, b: T2): T1 & T2;
         merge<T1>(a: T1): <T2>(b: T2) => T1 & T2;
 
@@ -1496,6 +1527,8 @@ declare namespace R {
          * Note that this functions preserves the JavaScript-style behavior for
          * modulo. For mathematical modulo see `mathMod`
          */
+        modulo(__: Placeholder, b: number): (a: number) => number;
+        modulo(__: Placeholder): (b: number, a: number) => number;
         modulo(a: number, b: number): number;
         modulo(a: number): (b: number) => number;
 
@@ -2282,6 +2315,8 @@ declare namespace R {
         /**
          * Subtracts two numbers. Equivalent to `a - b` but curried.
          */
+        subtract(__: Placeholder, b: number): (a: number) => number;
+        subtract(__: Placeholder): (b: number, a: number) => number;
         subtract(a: number, b: number): number;
         subtract(a: number): (b: number) => number;
 

types/ramda/ramda-tests.ts

@@ -124,6 +124,45 @@ class F2 {
     }
 };
 
+/** R.__ */
+() => {
+  R.concat(R.__, [4, 5, 6])([1, 2, 3]); // [1, 2, 3, 4, 5, 6]
+  R.concat(R.__)([4, 5, 6], [1, 2, 3]); // [1, 2, 3, 4, 5, 6]
+
+  R.contains(R.__, [1, 2, 3])(3); // true
+  R.contains<number>(R.__)([1, 2, 3], 3); // true
+
+  R.divide(R.__)(2, 42); // 21
+  R.divide(R.__, 2)(42); // 21
+
+  R.gt(R.__, 2)(10); // true
+  R.gt(R.__)(2, 10); // true
+
+  R.gte(R.__, 6)(2); // false
+  R.gte(R.__)(6, 2); // false
+
+  R.has(R.__, {x: 0, y: 0})('x'); // true;
+  R.has(R.__)({x: 0, y: 0}, 'x'); // true;
+
+  R.lt(R.__, 5)(10); // false
+  R.lt(R.__)(5, 10); // false
+
+  R.lte(R.__, 2)(1); // true
+  R.lte(R.__)(2, 1); // true
+
+  R.mathMod(R.__, 12)(15); // 3
+  R.mathMod(R.__)(12, 15); // 3
+
+  R.modulo(R.__, 2)(42); // 0
+  R.modulo(R.__)(2, 42); // 0
+
+  R.merge(R.__, {x: 0})({x: 5, y: 2}); // {x: 0, y: 2}
+  R.merge(R.__)({x: 0}, {x: 5, y: 2}); // {x: 0, y: 2}
+
+  R.subtract(R.__, 5)(17); // 12
+  R.subtract(R.__)(5, 17); // 12
+};
+
 () => {
     const addFour          = (a: number) => (b: number) => (c: number) => (d: number) => a + b + c + d;
     const uncurriedAddFour = R.uncurryN<number>(4, addFour);