fixup! Perform Promise<T> type conversion lazily

Author: ExE-Boss

lib/types.js

@@ -328,39 +328,52 @@ function generateTypeConversion(ctx, name, idlType, argAttrs = [], parentName, e
   }
 
   function generatePromise() {
-    str += `${name} = new Promise(resolve => resolve(${name}));`;
+    str += `
+      ${name} = new Promise(resolve => resolve(${name}));
+      Object.assign(${name}, {
+        then(onFulfilled, onRejected) {
+          return Promise.prototype.then.call(
+            this,
+    `;
 
-    if (idlType.idlType[0].idlType !== "void") {
+    if (idlType.idlType[0].idlType === "void") {
+      str += `
+            () => {
+              if (typeof onFulfilled === "function") {
+                return onFulfilled();
+              }
+            },
+      `;
+    } else {
       const convOnFulfilled = generateTypeConversion(ctx, "value", idlType.idlType[0], [], parentName,
         `${errPrefix} + " promise value"`);
       requires.merge(convOnFulfilled.requires);
 
-      const convOnRejected = generateTypeConversion(ctx, "reason", { idlType: "any" }, [], parentName,
-        `${errPrefix} + " promise value"`);
-      requires.merge(convOnRejected.requires);
-
       str += `
-        Object.assign(${name}, {
-          then(onFulfilled, onRejected) {
-            return Promise.prototype.then.call(
-              this,
-              value => {
-                ${convOnFulfilled.body.trim()}
-                if (typeof onFulfilled === "function") {
-                  return onFulfilled(value);
-                }
-              },
-              reason => {
-                ${convOnRejected.body.trim()}
-                if (typeof onRejected === "function") {
-                  return onRejected(reason);
-                }
+            value => {
+              ${convOnFulfilled.body.trim()}
+              if (typeof onFulfilled === "function") {
+                return onFulfilled(value);
               }
-            );
-          }
-        });
+            },
       `;
     }
+
+    const convOnRejected = generateTypeConversion(ctx, "reason", { idlType: "any" }, [], parentName,
+      `${errPrefix} + " promise value"`);
+    requires.merge(convOnRejected.requires);
+
+    str += `
+            reason => {
+              ${convOnRejected.body.trim()}
+              if (typeof onRejected === "function") {
+                return onRejected(reason);
+              }
+            }
+          );
+        }
+      });
+    `;
   }
 
   function generateFrozenArray() {

test/__snapshots__/test.js.snap

@@ -32,12 +32,14 @@ exports.convert = function convert(value, { context = \\"The provided value\\" }
         then(onFulfilled, onRejected) {
           return Promise.prototype.then.call(
             this,
+
             value => {
               value = conversions[\\"any\\"](value, { context: context + \\" promise value\\" });
               if (typeof onFulfilled === \\"function\\") {
                 return onFulfilled(value);
               }
             },
+
             reason => {
               reason = conversions[\\"any\\"](reason, { context: context + \\" promise value\\" });
               if (typeof onRejected === \\"function\\") {
@@ -3708,6 +3710,28 @@ exports.install = (globalObject, globalNames) => {
       {
         let curArg = arguments[0];
         curArg = new Promise(resolve => resolve(curArg));
+        Object.assign(curArg, {
+          then(onFulfilled, onRejected) {
+            return Promise.prototype.then.call(
+              this,
+
+              () => {
+                if (typeof onFulfilled === \\"function\\") {
+                  return onFulfilled();
+                }
+              },
+
+              reason => {
+                reason = conversions[\\"any\\"](reason, {
+                  context: \\"Failed to execute 'voidPromiseConsumer' on 'PromiseTypes': parameter 1\\" + \\" promise value\\"
+                });
+                if (typeof onRejected === \\"function\\") {
+                  return onRejected(reason);
+                }
+              }
+            );
+          }
+        });
         args.push(curArg);
       }
       return esValue[implSymbol].voidPromiseConsumer(...args);
@@ -3734,6 +3758,7 @@ exports.install = (globalObject, globalNames) => {
           then(onFulfilled, onRejected) {
             return Promise.prototype.then.call(
               this,
+
               value => {
                 value = conversions[\\"double\\"](value, {
                   context: \\"Failed to execute 'promiseConsumer' on 'PromiseTypes': parameter 1\\" + \\" promise value\\"
@@ -3742,6 +3767,7 @@ exports.install = (globalObject, globalNames) => {
                   return onFulfilled(value);
                 }
               },
+
               reason => {
                 reason = conversions[\\"any\\"](reason, {
                   context: \\"Failed to execute 'promiseConsumer' on 'PromiseTypes': parameter 1\\" + \\" promise value\\"
@@ -8913,12 +8939,14 @@ exports.convert = function convert(value, { context = \\"The provided value\\" }
         then(onFulfilled, onRejected) {
           return Promise.prototype.then.call(
             this,
+
             value => {
               value = conversions[\\"any\\"](value, { context: context + \\" promise value\\" });
               if (typeof onFulfilled === \\"function\\") {
                 return onFulfilled(value);
               }
             },
+
             reason => {
               reason = conversions[\\"any\\"](reason, { context: context + \\" promise value\\" });
               if (typeof onRejected === \\"function\\") {
@@ -12547,6 +12575,28 @@ exports.install = (globalObject, globalNames) => {
       {
         let curArg = arguments[0];
         curArg = new Promise(resolve => resolve(curArg));
+        Object.assign(curArg, {
+          then(onFulfilled, onRejected) {
+            return Promise.prototype.then.call(
+              this,
+
+              () => {
+                if (typeof onFulfilled === \\"function\\") {
+                  return onFulfilled();
+                }
+              },
+
+              reason => {
+                reason = conversions[\\"any\\"](reason, {
+                  context: \\"Failed to execute 'voidPromiseConsumer' on 'PromiseTypes': parameter 1\\" + \\" promise value\\"
+                });
+                if (typeof onRejected === \\"function\\") {
+                  return onRejected(reason);
+                }
+              }
+            );
+          }
+        });
         args.push(curArg);
       }
       return esValue[implSymbol].voidPromiseConsumer(...args);
@@ -12573,6 +12623,7 @@ exports.install = (globalObject, globalNames) => {
           then(onFulfilled, onRejected) {
             return Promise.prototype.then.call(
               this,
+
               value => {
                 value = conversions[\\"double\\"](value, {
                   context: \\"Failed to execute 'promiseConsumer' on 'PromiseTypes': parameter 1\\" + \\" promise value\\"
@@ -12581,6 +12632,7 @@ exports.install = (globalObject, globalNames) => {
                   return onFulfilled(value);
                 }
               },
+
               reason => {
                 reason = conversions[\\"any\\"](reason, {
                   context: \\"Failed to execute 'promiseConsumer' on 'PromiseTypes': parameter 1\\" + \\" promise value\\"