add: cut out trimming text logic for md note title and add unit test

browser/lib/markdownTextHelper.js

@@ -0,0 +1,39 @@
+/**
+ * @fileoverview Text trimmer for markdown note.
+ */
+
+/**
+ * @param {string} input
+ * @return {string}
+ */
+export function strip (input) {
+  var output = input
+  try {
+    output = output
+      .replace(/^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm, '$1')
+      .replace(/\n={2,}/g, '\n')
+      .replace(/~~/g, '')
+      .replace(/`{3}.*\n/g, '')
+      .replace(/<(.*?)>/g, '$1')
+      .replace(/^[=\-]{2,}\s*$/g, '')
+      .replace(/\[\^.+?\](: .*?$)?/g, '')
+      .replace(/\s{0,2}\[.*?\]: .*?$/g, '')
+      .replace(/!\[.*?\][\[\(].*?[\]\)]/g, '')
+      .replace(/\[(.*?)\][\[\(].*?[\]\)]/g, '$1')
+      .replace(/>/g, '')
+      .replace(/^\s{1,2}\[(.*?)\]: (\S+)( ".*?")?\s*$/g, '')
+      .replace(/^#{1,6}\s*([^#]*)\s*(#{1,6})?/gm, '$1')
+      .replace(/(`{3,})(.*?)\1/gm, '$2')
+      .replace(/^-{3,}\s*$/g, '')
+      .replace(/`(.+?)`/g, '$1')
+      .replace(/\n{2,}/g, '\n\n')
+  } catch (e) {
+    console.error(e)
+    return input
+  }
+  return output
+}
+
+export default {
+  strip,
+}

tests/lib/markdown-text-helper-test.js

@@ -0,0 +1,41 @@
+/**
+ * @fileoverview Unit test for browser/lib/markdown
+ */
+const test = require('ava')
+const markdown = require('browser/lib/markdownTextHelper')
+
+test(t => {
+  // [input, expected]
+  const testCases = [
+    // List
+    [' - ', ' '],
+    [' + ', ' '],
+    [' * ', ' '],
+    [' *   ', ' '],
+    [' 1. ', ' '],
+    [' 2.  ', ' '],
+    [' 10. ', ' '],
+    ["\t- ", "\t"],
+    ['- ', ''],
+    // Header with using line
+    ["\n==", "\n"],
+    ["\n===", "\n"],
+    ["test\n===", "test\n"],
+    // Code block
+    ["```test\n", ''],
+    ["```test\nhoge", 'hoge'],
+    // HTML tag
+    ['<>', ''],
+    ['<test>', 'test'],
+    ['hoge<test>', 'hogetest'],
+    ['<test>moge', 'testmoge'],
+    // Emphasis
+    ['~~', ''],
+    ['~~text~~', 'text'],
+  ]
+
+  testCases.forEach(testCase => {
+    const [input, expected] = testCase;
+    t.is(markdown.strip(input), expected, `Test for strip() input: ${input} expected: ${expected}`);
+  })
+})