improve ayakashi.join() type

ayakashi-io · Aug 25, 2019 · ddc491f · ddc491f
1 parent 16e3cdd
commit ddc491f
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Showing 2 changed files with 17 additions and 11 deletions.
diff --git a/__tests__/prelude/join.test.ts b/__tests__/prelude/join.test.ts
@@ -78,9 +78,10 @@ describe("join() tests", function() {
             });
         const result = await ayakashiInstance.extract("myLinkProp");
         expect(result).toEqual(["link1", "link2", "link3"]);
-        expect(ayakashiInstance.join({
+        const joined = ayakashiInstance.join({
             text: result
-        })).toEqual([{
+        });
+        expect(joined).toEqual([{
             text: "link1"
         }, {
             text: "link2"
@@ -102,18 +103,19 @@ describe("join() tests", function() {
             });
         const result = await ayakashiInstance.extract("myLinkProp");
         expect(result).toEqual(["link1", "link2", "link3"]);
-        expect(ayakashiInstance.join({
+        const joined = ayakashiInstance.join({
             text: result,
-            constant: "hello"
-        })).toEqual([{
+            constant: 5
+        });
+        expect(joined).toEqual([{
             text: "link1",
-            constant: "hello"
+            constant: 5
         }, {
             text: "link2",
-            constant: "hello"
+            constant: 5
         }, {
             text: "link3",
-            constant: "hello"
+            constant: 5
         }]);
         await ayakashiInstance.__connection.release();
     });

diff --git a/src/prelude/actions/meta.ts b/src/prelude/actions/meta.ts
@@ -98,9 +98,11 @@ ayakashi.registerExtractor("id", function() {
  * Groups together multiple sets of related data.
  * Learn more here: https://ayakashi.io/docs/guide/data-extraction.html#grouping-extracted-data
 */
-    join: (obj: {[key: string]: unknown}) => {[key: string]: unknown}[];
+    join: <T>(obj: T) => {[P in keyof T]: valueof<T[P]>}[];
 }
 
+type valueof<T> = T extends (infer U)[] ? U : T;
+
 export function attachMetaActions(
     ayakashiInstance: IAyakashiInstance | IRenderlessAyakashiInstance,
     connection: IConnection
@@ -208,6 +210,7 @@ export function attachMetaActions(
         };
     };
 
+    //@ts-ignore
     ayakashiInstance.join = function(obj) {
         if (!obj || typeof obj !== "object" || Object.keys(obj).length === 0) {
             throw new Error("Invalid object");
@@ -238,7 +241,7 @@ export function attachMetaActions(
         }
         //check if we only have non-array values
         if (max === 0) {
-            let j: {[key: string]: unknown} = {};
+            let j = {};
             if (nonArrays.length > 0) {
                 for (const nonArray of nonArrays) {
                     j = {...j, ...nonArray};
@@ -250,9 +253,10 @@ export function attachMetaActions(
             //create the joined value
             const joined = [];
             for (let i = 0; i < max; i += 1) {
-                let j: {[key: string]: unknown} = {};
+                let j = {};
                 for (const [key, val] of Object.entries(obj)) {
                     if (Array.isArray(val)) {
+                        //@ts-ignore
                         j[key] = val[i];
                     }
                 }