transplant option-parser from growi-plugin-lsx

packages/growi-commons/src/plugin/util/option-parser.js

@@ -0,0 +1,57 @@
+class OptionParser {
+
+  /**
+   * parse range expression
+   *
+   * ex:
+   *  1:2 -> { start: 1, end: 2 }
+   *  1:  -> { start: 1, end: -1 }
+   *  2+3 -> { start: 1, end: 5 }
+   *
+   * @static
+   * @param {any} str
+   * @returns
+   *
+   * @memberOf OptionParser
+   */
+  static parseRange(str) {
+    if (str == null) {
+      return null;
+    }
+
+    // see: https://regex101.com/r/w4KCwC/4
+    const match = str.match(/^(-?[0-9]+)(([:+]{1})(-?[0-9]+)?)?$/);
+    if (!match) {
+      return null;
+    }
+
+    // determine start
+    let start;
+    let end;
+
+    // has operator
+    if (match[3] != null) {
+      start = +match[1];
+      const operator = match[3];
+
+      // determine end
+      if (operator === ':') {
+        end = +match[4] || -1; // set last(-1) if undefined
+      }
+      else if (operator === '+') {
+        end = +match[4] || 0; // plus zero if undefined
+        end += start;
+      }
+    }
+    // don't have operator
+    else {
+      start = 1;
+      end = +match[1];
+    }
+
+    return { start, end };
+  }
+
+}
+
+module.exports = OptionParser;

packages/growi-commons/src/test/plugin/util/option-parser.test.js

@@ -0,0 +1,24 @@
+import each from 'jest-each';
+
+require('module-alias/register');
+
+const OptionParser = require('@src/plugin/util/option-parser');
+
+describe('option-parser', () => {
+
+  test('.parseRange(null) returns null', () => {
+    expect(OptionParser.parseRange(null)).toBeNull();
+  });
+
+  each`
+    arg
+    ${'aaa'}
+    ${'5++2'}
+    ${'5:+2'}
+  `.describe.only('.parseRange(\'$arg\')', ({ arg }) => {
+    test('returns null', () => {
+      expect(OptionParser.parseRange(arg)).toBeNull();
+    });
+  });
+
+});