add polyfill originals to test against

Author: lobsterkatie

packages/utils/.gitignore

@@ -1,3 +1,6 @@
 # symlinks to the folders in `build`, needed for tests
 cjs
 esm
+
+# needed so we can test our versions of polyfills against Sucrase and Rollup's originals
+!test/buildPolyfills/originals.d.ts

packages/utils/test/buildPolyfills/originals.d.ts

@@ -0,0 +1,23 @@
+// NOTE: Unlike other types files, this is NOT auto-generated by our build scripts. Since these functions are the
+// originals of functions we adapted from Rollup and Sucrase, there's no reason they should ever change, but if they do,
+// this file needs to be regenerated, by running
+//   `yarn tsc --allowJs --skipLibCheck --declaration --emitDeclarationOnly test/buildPolyfills/originals.js`
+// from within the `utils` package. Keep in mind that running that command will clobber this note, so make sure to copy
+// it before you regenerate the types, so you can add it back in.)
+
+export function _asyncNullishCoalesce(lhs: any, rhsFn: any): Promise<any>;
+export function _asyncOptionalChain(ops: any): Promise<any>;
+export function _asyncOptionalChainDelete(ops: any): Promise<any>;
+export function _createNamedExportFrom(obj: any, localName: any, importedName: any): void;
+export function _createStarExport(obj: any): void;
+export function _interopDefault(e: any): any;
+export function _interopNamespace(e: any): any;
+export function _interopNamespaceDefaultOnly(e: any): {
+  __proto__: any;
+  default: any;
+};
+export function _interopRequireDefault(obj: any): any;
+export function _interopRequireWildcard(obj: any): any;
+export function _nullishCoalesce(lhs: any, rhsFn: any): any;
+export function _optionalChain(ops: any): any;
+export function _optionalChainDelete(ops: any): any;

packages/utils/test/buildPolyfills/originals.js

@@ -0,0 +1,147 @@
+// Originals of the buildPolyfills from Sucrase and Rollup we use (which we have adapted in various ways), preserved here for testing, to prove that
+// the modified versions do the same thing the originals do.
+
+// From Sucrase
+export async function _asyncNullishCoalesce(lhs, rhsFn) {
+  if (lhs != null) {
+    return lhs;
+  } else {
+    return await rhsFn();
+  }
+}
+
+// From Sucrase
+export async function _asyncOptionalChain(ops) {
+  let lastAccessLHS = undefined;
+  let value = ops[0];
+  let i = 1;
+  while (i < ops.length) {
+    const op = ops[i];
+    const fn = ops[i + 1];
+    i += 2;
+    if ((op === 'optionalAccess' || op === 'optionalCall') && value == null) {
+      return undefined;
+    }
+    if (op === 'access' || op === 'optionalAccess') {
+      lastAccessLHS = value;
+      value = await fn(value);
+    } else if (op === 'call' || op === 'optionalCall') {
+      value = await fn((...args) => value.call(lastAccessLHS, ...args));
+      lastAccessLHS = undefined;
+    }
+  }
+  return value;
+}
+
+// From Sucrase
+export async function _asyncOptionalChainDelete(ops) {
+  const result = await _asyncOptionalChain(ops);
+  // by checking for loose equality to `null`, we catch both `null` and `undefined`
+  return result == null ? true : result;
+}
+
+// From Sucrase
+export function _createNamedExportFrom(obj, localName, importedName) {
+  Object.defineProperty(exports, localName, { enumerable: true, get: () => obj[importedName] });
+}
+
+// From Sucrase
+export function _createStarExport(obj) {
+  Object.keys(obj)
+    .filter(key => key !== 'default' && key !== '__esModule')
+    .forEach(key => {
+      // eslint-disable-next-line no-prototype-builtins
+      if (exports.hasOwnProperty(key)) {
+        return;
+      }
+      Object.defineProperty(exports, key, { enumerable: true, get: () => obj[key] });
+    });
+}
+
+// From Rollup
+export function _interopDefault(e) {
+  return e && e.__esModule ? e['default'] : e;
+}
+
+// From Rollup
+export function _interopNamespace(e) {
+  if (e && e.__esModule) return e;
+  var n = Object.create(null);
+  if (e) {
+    // eslint-disable-next-line guard-for-in
+    for (var k in e) {
+      n[k] = e[k];
+    }
+  }
+  n['default'] = e;
+  return n;
+}
+
+export function _interopNamespaceDefaultOnly(e) {
+  return {
+    __proto__: null,
+    default: e,
+  };
+}
+
+// From Sucrase
+export function _interopRequireDefault(obj) {
+  return obj && obj.__esModule ? obj : { default: obj };
+}
+
+// From Sucrase
+export function _interopRequireWildcard(obj) {
+  if (obj && obj.__esModule) {
+    return obj;
+  } else {
+    var newObj = {};
+    if (obj != null) {
+      for (var key in obj) {
+        if (Object.prototype.hasOwnProperty.call(obj, key)) {
+          newObj[key] = obj[key];
+        }
+      }
+    }
+    newObj.default = obj;
+    return newObj;
+  }
+}
+
+// From Sucrase
+export function _nullishCoalesce(lhs, rhsFn) {
+  if (lhs != null) {
+    return lhs;
+  } else {
+    return rhsFn();
+  }
+}
+
+// From Sucrase
+export function _optionalChain(ops) {
+  let lastAccessLHS = undefined;
+  let value = ops[0];
+  let i = 1;
+  while (i < ops.length) {
+    const op = ops[i];
+    const fn = ops[i + 1];
+    i += 2;
+    if ((op === 'optionalAccess' || op === 'optionalCall') && value == null) {
+      return undefined;
+    }
+    if (op === 'access' || op === 'optionalAccess') {
+      lastAccessLHS = value;
+      value = fn(value);
+    } else if (op === 'call' || op === 'optionalCall') {
+      value = fn((...args) => value.call(lastAccessLHS, ...args));
+      lastAccessLHS = undefined;
+    }
+  }
+  return value;
+}
+
+// From Sucrase
+export function _optionalChainDelete(ops) {
+  const result = _optionalChain(ops);
+  // by checking for loose equality to `null`, we catch both `null` and `undefined`
+  return result == null ? true : result;
+}