fix assoc typing, suggested in @whitecolor's #90 and and #119

Author: KiaraGrouwstra

index.d.ts

@@ -382,10 +382,30 @@ declare namespace R {
         /**
          * Makes a shallow clone of an object, setting or overriding the specified property with the given value.
          */
-        assoc<T,U>(prop: Prop, val: T, obj: U): {prop: T} & U;
-        assoc<T>(prop: Prop, val: T): <U>(obj: U) => {prop: T} & U;
-        assoc<T,U>(prop: Prop): CurriedFn2<T,U, {prop: T} & U>;
-        // assoc<T,U>: CurriedFn3<Prop, T, U, {prop: T} & U>;
+
+        // extend object with new property
+        assoc<T, U extends Struct<any>, K extends keyof U>(prop: K, val: T, obj: U): {[P in K]: T} & U;
+        assoc<T, U extends Struct<any>, K extends keyof U>(prop: K, val: T): (obj: U) => {[P in K]: T} & U; // generics too early?
+        assoc<T, U extends Struct<any>, K extends keyof U>(prop: K): CurriedFn2<T,U, {[P in K]: T} & U>; // generics too early?
+        // assoc<T, U extends Struct<any>, K extends keyof U>: CurriedFn3<K, T, U, {[P in K]: T} & U>;
+
+        // // homogeneous object
+        // assoc<T, U extends Struct<T>>(prop: Prop, val: T, obj: U): U;
+        // assoc<T>(prop: Prop, val: T): <U extends Struct<T>>(obj: U) => U;
+        // assoc<T, U extends Struct<T>>(prop: Prop): CurriedFn2<T, U, U>; // generics too early?
+        // // assoc<T, U extends Struct<T>>: CurriedFn3<Prop, T, U, U>;
+
+        // any object as long as the type remains unchanged
+        assoc<T>(prop: Prop, val: any, obj: T): T;
+        assoc(prop: Prop, val: any): <T>(obj: T) => T;
+        assoc<T>(prop: Prop): CurriedFn2<any, T, T>; // generics too early?
+        // assoc<T>: CurriedFn3<Prop, any, T, T>;
+
+        // // broken alternative trying to be dynamic, seems not yet possible in current TS versions
+        // assoc<T,U>(prop: Prop, val: T, obj: U): {prop: T} & U;
+        // assoc<T>(prop: Prop, val: T): <U>(obj: U) => {prop: T} & U;
+        // assoc<T,U>(prop: Prop): CurriedFn2<T,U, {prop: T} & U>;
+        // // assoc<T,U>: CurriedFn3<Prop, T, U, {prop: T} & U>;
 
 
         /**

test.ts

@@ -1266,16 +1266,16 @@ class Rectangle {
       y: number;
     }
     // var xLens = R.lens(R.prop('x'), R.assoc('x'));
-    var xLens = R.lens<number, xy>(R.prop('x'), R.assoc('x'));
-    // var xLens = R.lens<number>(R.prop('x'))(R.assoc('x'));
+    // var xLens = R.lens<number, xy>(R.prop('x'), R.assoc('x'));
+    var xLens = R.lens<number>(R.prop('x'))(R.assoc('x'));
     // ^ works with only 1 generic, for curried version managed to split the inferred generic from the manual generic
-    R.view(xLens, {x: 1, y: 2});            //=> 1
-    R.set(xLens, 4, {x: 1, y: 2});          //=> {x: 4, y: 2}
-    R.set(xLens)(4, {x: 1, y: 2});          //=> {x: 4, y: 2}
-    R.set(xLens, 4)({x: 1, y: 2});          //=> {x: 4, y: 2}
-    R.over(xLens, R.negate, {x: 1, y: 2});  //=> {x: -1, y: 2}
-    R.over(xLens, R.negate)({x: 1, y: 2});  //=> {x: -1, y: 2}
-    R.over(xLens)(R.negate, {x: 1, y: 2});  //=> {x: -1, y: 2}
+    let r1: number = R.view(xLens, {x: 1, y: 2});            //=> 1
+    let r2: xy = R.set(xLens, 4, {x: 1, y: 2});          //=> {x: 4, y: 2}
+    let r3: xy = R.set(xLens)(4, {x: 1, y: 2});          //=> {x: 4, y: 2}
+    let r4: xy = R.set(xLens, 4)({x: 1, y: 2});          //=> {x: 4, y: 2}
+    let r5: xy = R.over(xLens, R.negate, {x: 1, y: 2});  //=> {x: -1, y: 2}
+    let r6: xy = R.over(xLens, R.negate)({x: 1, y: 2});  //=> {x: -1, y: 2}
+    let r7: xy = R.over(xLens)(R.negate, {x: 1, y: 2});  //=> {x: -1, y: 2}
 }
 () => {
     var headLens = R.lensIndex(0);