feat: add String.dedent polyfill

src/dependencies.ts

@@ -20,9 +20,13 @@ import { Command } from 'https://deno.land/x/cmd@v1.2.0/commander/index.ts';
 import { getUnityChangeset as getUnityChangeSet } from 'https://deno.land/x/unity_changeset@2.0.0/src/index.ts';
 import { Buffer } from 'https://deno.land/std@0.151.0/io/buffer.ts';
 
-// Internally managed
+// Internally managed packages
 import waitUntil from './modules/wait-until.ts';
 import { core, exec } from './modules/actions/index.ts';
+import { dedent } from './modules/dedent.ts';
+
+// Polyfill for https://github.com/tc39/proposal-string-dedent
+String.dedent = dedent;
 
 class Writable {
   constructor() {

src/modules/dedent.ts

@@ -0,0 +1,54 @@
+/* eslint-disable unicorn/no-array-reduce,unicorn/explicit-length-check,padding-line-between-statements,github/array-foreach,unicorn/no-array-for-each */
+
+// Source: https://github.com/tamino-martinius/node-ts-dedent/blob/master/src/index.ts
+export function dedent(template: TemplateStringsArray | string, ...values: unknown[]): string {
+  let strings = Array.from(typeof template === 'string' ? [template] : template);
+
+  // 1. Remove trailing whitespace.
+  strings[strings.length - 1] = strings[strings.length - 1].replace(/\r?\n([\t ]*)$/, '');
+
+  // 2. Find all line breaks to determine the highest common indentation level.
+  const indentLengths = strings.reduce((arr, str) => {
+    const matches = str.match(/\n([\t ]+|(?!\s).)/g);
+    if (matches) {
+      return arr.concat(matches.map((match) => match.match(/[\t ]/g)?.length ?? 0));
+    }
+    return arr;
+  }, <number[]>[]);
+
+  // 3. Remove the common indentation from all strings.
+  if (indentLengths.length) {
+    const pattern = new RegExp(`\n[\t ]{${Math.min(...indentLengths)}}`, 'g');
+
+    strings = strings.map((str) => str.replace(pattern, '\n'));
+  }
+
+  // 4. Remove leading whitespace.
+  strings[0] = strings[0].replace(/^\r?\n/, '');
+
+  // 5. Perform interpolation.
+  let string = strings[0];
+
+  values.forEach((value, i) => {
+    // 5.1 Read current indentation level
+    const indentations = string.match(/(?:^|\n)( *)$/);
+    const indentation = indentations ? indentations[1] : '';
+    let indentedValue = value;
+
+    // 5.2 Add indentation to values with multiline strings
+    if (typeof value === 'string' && value.includes('\n')) {
+      indentedValue = String(value)
+        .split('\n')
+        .map((str, i) => {
+          return i === 0 ? str : `${indentation}${str}`;
+        })
+        .join('\n');
+    }
+
+    string += indentedValue + strings[i + 1];
+  });
+
+  return string;
+}
+
+export default dedent;