Add Dynamic import (rescript-lang#178)

* upgrade rescript to v11

* format files

* add import

* update tests

* update CHANGELOG.md

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Add `Dict.forEach`, `Dict.forEachWithKey` and `Dict.mapValues` https://github.com/rescript-association/rescript-core/pull/181
 - Remove internal xxxU helper functions that are not needed anymore in uncurried mode. https://github.com/rescript-association/rescript-core/pull/191
 - Rename `Object.empty` to `Object.make` for consistency.
+- Add dynamic `import`. https://github.com/rescript-association/rescript-core/pull/178
 
 ## 1.0.0
 

src/RescriptCore.res

@@ -52,6 +52,43 @@ external null: Core__Nullable.t<'a> = "#null"
 external undefined: Core__Nullable.t<'a> = "#undefined"
 external typeof: 'a => Core__Type.t = "#typeof"
 
+/**
+`import(value)` dynamically import a value or function from a ReScript
+module. The import call will return a `promise`, resolving to the dynamically loaded
+value.
+
+## Examples
+
+`MathUtils.res` file:
+
+```rescript
+let add = (a, b) => a + b
+let sub = (a, b) => a - b
+```
+In other file you can import the `add` value defined in `MathUtils.res`
+
+```rescript
+let main = async () => {
+  let add = await import(MathUtils.add)
+  let onePlusOne = add(1, 1)
+  Console.log(onePlusOne)
+}
+```
+
+Compiles to:
+
+```javascript
+async function main() {
+  var add = await import("./MathUtils.mjs").then(function(m) {
+    return m.add;
+  });
+  var onePlusOne = add(1, 1);
+  console.log(onePlusOne);
+}
+```
+*/
+external import: 'a => promise<'a> = "#import"
+
 type t<'a> = Js.t<'a>
 module MapperRt = Js.MapperRt
 module Internal = Js.Internal

test/ImportTests.mjs

@@ -0,0 +1,23 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
+
+import * as Test from "./Test.mjs";
+
+async function main() {
+  var eq = await import("./IntTests.mjs").then(function (m) {
+        return m.eq;
+      });
+  return Test.run([
+              [
+                "ImportTests.res",
+                5,
+                22,
+                55
+              ],
+              "dynamic import - Int tests - eq"
+            ], 1, eq, 1);
+}
+
+export {
+  main ,
+}
+/* Test Not a pure module */

test/ImportTests.res

@@ -0,0 +1,8 @@
+open RescriptCore
+
+let main = async () => {
+  let eq = await import(IntTests.eq)
+  Test.run(__POS_OF__("dynamic import - Int tests - eq"), 1, eq, 1)
+}
+
+main->ignore