From f8bee7fe05fab98a6ec077a1132ffb995028cb84 Mon Sep 17 00:00:00 2001
From: MorevM <max.seainside@gmail.com>
Date: Sun, 24 Mar 2024 15:50:36 +0300
Subject: [PATCH] feat(strings): Add `stripIndent` utility

---
 src/strings/index.ts                          |  1 +
 src/strings/strip-indent/strip-indent.test.ts | 56 ++++++++++++++++++
 src/strings/strip-indent/strip-indent.ts      | 58 +++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 src/strings/strip-indent/strip-indent.test.ts
 create mode 100644 src/strings/strip-indent/strip-indent.ts

diff --git a/src/strings/index.ts b/src/strings/index.ts
index ab2231b..b77a738 100644
--- a/src/strings/index.ts
+++ b/src/strings/index.ts
@@ -11,4 +11,5 @@ export * from './quote/quote';
 export * from './random-string/random-string';
 export * from './romanize/romanize';
 export * from './snake-case/snake-case';
+export * from './strip-indent/strip-indent';
 export * from './unquote/unquote';
diff --git a/src/strings/strip-indent/strip-indent.test.ts b/src/strings/strip-indent/strip-indent.test.ts
new file mode 100644
index 0000000..5a7f1eb
--- /dev/null
+++ b/src/strings/strip-indent/strip-indent.test.ts
@@ -0,0 +1,56 @@
+import { stripIndent } from './strip-indent';
+
+describe('strip-indent', () => {
+	it('Returns the string as is if there is no extra indentation and leading/trailing linebreaks', () => {
+		expect(stripIndent('')).toBe('');
+		expect(stripIndent('foo')).toBe('foo');
+		expect(stripIndent('foo\n\t\t\tbar\n\nbar')).toBe('foo\n\t\t\tbar\n\nbar');
+	});
+
+	it('Removes leading/trailing linebreaks and lines containing only space\tab characters by default', () => {
+		expect(stripIndent('\nfoo\n')).toBe('foo');
+		expect(stripIndent('\n\t   \nfoo\n\t\t  \t\t\n')).toBe('foo');
+	});
+
+	it('Preserves leading linebreaks and lines containing only space\tab characters using `trimLeadingSpacings: false`', () => {
+		expect(stripIndent('\nfoo\n', { trimLeadingSpacings: false })).toBe('\nfoo');
+		expect(stripIndent('\n\t   \nfoo\n\t\t  \t\t\n', { trimLeadingSpacings: false })).toBe('\n\t   \nfoo');
+	});
+
+	it('Preserves trailing linebreaks and lines containing only space\tab characters using `trimTrailingSpacings: false`', () => {
+		expect(stripIndent('\nfoo\n', { trimTrailingSpacings: false })).toBe('foo\n');
+		expect(stripIndent('\n\t   \nfoo\n\t\t  \t\t\n', { trimTrailingSpacings: false })).toBe('foo\n\t\t  \t\t\n');
+	});
+
+	it('Removes extra indentation and linebreaks', () => {
+		expect(stripIndent(`
+
+			<div>
+				<div></div>
+			</div>
+
+		`)).toBe('<div>\n\t<div></div>\n</div>');
+	});
+
+	it('Removes extra indentation and linebreaks considering extra spacings', () => {
+		expect(stripIndent(`
+
+			<div>
+				<div></div>
+				  <div></div>
+						<div></div>
+			</div>
+
+		`)).toBe('<div>\n\t<div></div>\n\t  <div></div>\n\t\t\t<div></div>\n</div>');
+	});
+
+	it('Removes only extra indentation using `trim[X]Spacings: false`', () => {
+		expect(stripIndent(`
+
+			<div>
+				<div></div>
+			</div>
+
+		`, { trimLeadingSpacings: false, trimTrailingSpacings: false })).toBe('\n\n<div>\n\t<div></div>\n</div>\n\n\t\t');
+	});
+});
diff --git a/src/strings/strip-indent/strip-indent.ts b/src/strings/strip-indent/strip-indent.ts
new file mode 100644
index 0000000..a9b4145
--- /dev/null
+++ b/src/strings/strip-indent/strip-indent.ts
@@ -0,0 +1,58 @@
+import { mergeObjects } from '../../objects/merge-objects/merge-objects';
+
+const _getMinimalIndent = (input: string) => {
+	const match = input.match(/^[\t ]*(?=\S)/gm);
+	if (!match) return 0;
+
+	return match.reduce((minimalIndentation, spacings) =>
+		Math.min(minimalIndentation, spacings.length), Infinity);
+};
+
+
+type Options = {
+	/**
+	 * Whether to remove leading linebreaks and spacings (before the first non-space character)
+	 *
+	 * @default true
+	 */
+	trimLeadingSpacings: boolean;
+
+	/**
+	 * Whether to remove trailing linebreaks and spacings (after the last non-space character)
+	 *
+	 * @default true
+	 */
+	trimTrailingSpacings: boolean;
+};
+
+const DEFAULTS: Options = {
+	trimLeadingSpacings: true,
+	trimTrailingSpacings: true,
+};
+
+const _applyOptions = (input: string, options: Options) => {
+	options.trimLeadingSpacings && (input = input.replace(/^\n\s*(?=\S)/, ''));
+	options.trimTrailingSpacings && (input = input.replace(/\n\s*$/, ''));
+
+	return input;
+};
+
+/**
+ * Removes an extra indentation of the string. \
+ * Useful to work with template literal strings.
+ *
+ * @param   input         String to remove an extra indentation.
+ * @param   userOptions   Extra options.
+ *
+ * @returns               The string with minimal required indentation.
+ */
+export const stripIndent = (input: string, userOptions?: Partial<Options>) => {
+	const options = mergeObjects(DEFAULTS, userOptions) as Required<Options>;
+
+	const minIndent = _getMinimalIndent(input);
+	if (minIndent === 0) return _applyOptions(input, options);
+
+	const regex = new RegExp(`^[\t ]{${minIndent}}`, 'gm');
+
+	return _applyOptions(input, options).replace(regex, '');
+};