feat: local and remote shim modules (#128)

README.md

@@ -222,7 +222,6 @@ await build({
   scriptModule: false, // node-fetch 3+ only supports ESM
   // ...etc...
   shims: {
-    // ...etc...
     custom: [{
       package: {
         name: "node-fetch",
@@ -239,9 +238,7 @@ await build({
       }],
     }, {
       // this is what `blob: true` does internally
-      package: {
-        name: "buffer", // uses node's "buffer" module
-      },
+      module: "buffer", // uses node's "buffer" module
       globalNames: ["Blob"],
     }, {
       // this is what `domException: true` does internally
@@ -271,6 +268,35 @@ await build({
 });
 ```
 
+#### Local or Remote Shim Modules
+
+Custom shims can also refer to local or remote modules:
+
+```ts
+await build({
+  // ...etc...
+  shims: {
+    custom: [{
+      module: "./my-custom-fetch-implementation.ts",
+      globalNames: ["fetch"],
+    }, {
+      module: "https://deno.land/x/some_remote_shim_module/mod.ts",
+      globalNames: ["setTimeout"],
+    }],
+  },
+});
+```
+
+Where `my-custom-fetch-implementation.ts` contains:
+
+```ts
+export function fetch(/* etc... */) {
+  // etc...
+}
+```
+
+This is useful in situations where you want to implement your own shim.
+
 ### Specifier to Npm Package Mappings
 
 In most cases, dnt won't know about an npm package being available for one of your dependencies and will download remote modules to include in your package. There are scenarios though where an npm package may exist and you want to use it instead. This can be done by providing a specifier to npm package mapping.

lib/pkg/dnt_wasm.js

@@ -2,26 +2,6 @@ import { fetch_specifier } from './snippets/dnt-wasm-a15ef721fa5290c5/helpers.js
 
 let wasm;
 
-const heap = new Array(32).fill(undefined);
-
-heap.push(undefined, null, true, false);
-
-function getObject(idx) { return heap[idx]; }
-
-let heap_next = heap.length;
-
-function dropObject(idx) {
-    if (idx < 36) return;
-    heap[idx] = heap_next;
-    heap_next = idx;
-}
-
-function takeObject(idx) {
-    const ret = getObject(idx);
-    dropObject(idx);
-    return ret;
-}
-
 let cachedTextDecoder = new TextDecoder('utf-8', { ignoreBOM: true, fatal: true });
 
 cachedTextDecoder.decode();
@@ -38,6 +18,12 @@ function getStringFromWasm0(ptr, len) {
     return cachedTextDecoder.decode(getUint8Memory0().subarray(ptr, ptr + len));
 }
 
+const heap = new Array(32).fill(undefined);
+
+heap.push(undefined, null, true, false);
+
+let heap_next = heap.length;
+
 function addHeapObject(obj) {
     if (heap_next === heap.length) heap.push(heap.length + 1);
     const idx = heap_next;
@@ -47,6 +33,8 @@ function addHeapObject(obj) {
     return idx;
 }
 
+function getObject(idx) { return heap[idx]; }
+
 let WASM_VECTOR_LEN = 0;
 
 let cachedTextEncoder = new TextEncoder('utf-8');
@@ -110,6 +98,18 @@ function getInt32Memory0() {
     return cachegetInt32Memory0;
 }
 
+function dropObject(idx) {
+    if (idx < 36) return;
+    heap[idx] = heap_next;
+    heap_next = idx;
+}
+
+function takeObject(idx) {
+    const ret = getObject(idx);
+    dropObject(idx);
+    return ret;
+}
+
 function debugString(val) {
     // primitive types
     const type = typeof val;
@@ -260,22 +260,6 @@ async function init(input) {
     }
     const imports = {};
     imports.wbg = {};
-    imports.wbg.__wbindgen_object_drop_ref = function(arg0) {
-        takeObject(arg0);
-    };
-    imports.wbg.__wbindgen_cb_drop = function(arg0) {
-        const obj = takeObject(arg0).original;
-        if (obj.cnt-- == 1) {
-            obj.a = 0;
-            return true;
-        }
-        var ret = false;
-        return ret;
-    };
-    imports.wbg.__wbindgen_string_new = function(arg0, arg1) {
-        var ret = getStringFromWasm0(arg0, arg1);
-        return addHeapObject(ret);
-    };
     imports.wbg.__wbindgen_json_parse = function(arg0, arg1) {
         var ret = JSON.parse(getStringFromWasm0(arg0, arg1));
         return addHeapObject(ret);
@@ -288,6 +272,18 @@ async function init(input) {
         getInt32Memory0()[arg0 / 4 + 1] = len0;
         getInt32Memory0()[arg0 / 4 + 0] = ptr0;
     };
+    imports.wbg.__wbindgen_object_drop_ref = function(arg0) {
+        takeObject(arg0);
+    };
+    imports.wbg.__wbindgen_cb_drop = function(arg0) {
+        const obj = takeObject(arg0).original;
+        if (obj.cnt-- == 1) {
+            obj.a = 0;
+            return true;
+        }
+        var ret = false;
+        return ret;
+    };
     imports.wbg.__wbg_fetchspecifier_bcacee1e00bcee02 = function(arg0, arg1) {
         try {
             var ret = fetch_specifier(getStringFromWasm0(arg0, arg1));
@@ -309,6 +305,10 @@ async function init(input) {
         var ret = typeof(val) === 'object' && val !== null;
         return ret;
     };
+    imports.wbg.__wbindgen_string_new = function(arg0, arg1) {
+        var ret = getStringFromWasm0(arg0, arg1);
+        return addHeapObject(ret);
+    };
     imports.wbg.__wbg_new_693216e109162396 = function() {
         var ret = new Error();
         return addHeapObject(ret);
@@ -407,8 +407,8 @@ async function init(input) {
     imports.wbg.__wbindgen_throw = function(arg0, arg1) {
         throw new Error(getStringFromWasm0(arg0, arg1));
     };
-    imports.wbg.__wbindgen_closure_wrapper445 = function(arg0, arg1, arg2) {
-        var ret = makeMutClosure(arg0, arg1, 197, __wbg_adapter_24);
+    imports.wbg.__wbindgen_closure_wrapper510 = function(arg0, arg1, arg2) {
+        var ret = makeMutClosure(arg0, arg1, 208, __wbg_adapter_24);
         return addHeapObject(ret);
     };
 

lib/shims.test.ts

@@ -2,6 +2,7 @@
 
 import { assertEquals } from "./test.deps.ts";
 import { shimOptionsToTransformShims } from "./shims.ts";
+import { PackageShim } from "../transform.ts";
 
 Deno.test("should get when all true", () => {
   const result = shimOptionsToTransformShims({
@@ -80,7 +81,13 @@ Deno.test("should get for inner deno namespace", () => {
   });
 
   assertEquals(result.shims.length, 1);
-  assertEquals(result.shims[0].package.name, "@deno/shim-deno-test");
+  assertEquals(
+    (result.shims[0] as PackageShim).package.name,
+    "@deno/shim-deno-test",
+  );
   assertEquals(result.testShims.length, 1);
-  assertEquals(result.testShims[0].package.name, "@deno/shim-deno-test");
+  assertEquals(
+    (result.testShims[0] as PackageShim).package.name,
+    "@deno/shim-deno-test",
+  );
 });

lib/shims.ts

@@ -165,9 +165,7 @@ function getCryptoShim(): Shim {
 
 function getBlobShim(): Shim {
   return {
-    package: {
-      name: "buffer",
-    },
+    module: "buffer",
     globalNames: ["Blob"],
   };
 }