Updated the files.

my-app/node_modules/@jridgewell/set-array/src/set-array.ts

@@ -0,0 +1,55 @@
+/**
+ * Gets the index associated with `key` in the backing array, if it is already present.
+ */
+export let get: (strarr: SetArray, key: string) => number | undefined;
+
+/**
+ * Puts `key` into the backing array, if it is not already present. Returns
+ * the index of the `key` in the backing array.
+ */
+export let put: (strarr: SetArray, key: string) => number;
+
+/**
+ * Pops the last added item out of the SetArray.
+ */
+export let pop: (strarr: SetArray) => void;
+
+/**
+ * SetArray acts like a `Set` (allowing only one occurrence of a string `key`), but provides the
+ * index of the `key` in the backing array.
+ *
+ * This is designed to allow synchronizing a second array with the contents of the backing array,
+ * like how in a sourcemap `sourcesContent[i]` is the source content associated with `source[i]`,
+ * and there are never duplicates.
+ */
+export class SetArray {
+  private declare _indexes: { [key: string]: number | undefined };
+  declare array: readonly string[];
+
+  constructor() {
+    this._indexes = { __proto__: null } as any;
+    this.array = [];
+  }
+
+  static {
+    get = (strarr, key) => strarr._indexes[key];
+
+    put = (strarr, key) => {
+      // The key may or may not be present. If it is present, it's a number.
+      const index = get(strarr, key);
+      if (index !== undefined) return index;
+
+      const { array, _indexes: indexes } = strarr;
+
+      return (indexes[key] = (array as string[]).push(key) - 1);
+    };
+
+    pop = (strarr) => {
+      const { array, _indexes: indexes } = strarr;
+      if (array.length === 0) return;
+
+      const last = (array as string[]).pop()!;
+      indexes[last] = undefined;
+    };
+  }
+}