chore(TypeScript): refactor objects into classes

fix: `Nil`(null, undefined) now renders as empty string
change: `parser.parseValue()` renamed to `parser.parseOutput`
change: registered tags/filters become static and shared across different liquid instances

src/parser/whitespace-ctrl.ts

@@ -0,0 +1,48 @@
+import { assign } from 'src/util/underscore'
+import TagToken from './tag-token'
+import OutputToken from './output-token'
+import HTMLToken from './html-token'
+
+export default function whiteSpaceCtrl (tokens, options) {
+  options = assign({ greedy: true }, options)
+  let inRaw = false
+
+  tokens.forEach((token, i) => {
+    if (shouldTrimLeft(token, inRaw, options)) {
+      trimLeft(tokens[i - 1], options.greedy)
+    }
+
+    if (token.type === 'tag' && token.name === 'raw') inRaw = true
+    if (token.type === 'tag' && token.name === 'endraw') inRaw = false
+
+    if (shouldTrimRight(token, inRaw, options)) {
+      trimRight(tokens[i + 1], options.greedy)
+    }
+  })
+}
+
+function shouldTrimLeft (token, inRaw, options) {
+  if (inRaw) return false
+  if (token.type === 'tag') return token.trim_left || options.trim_tag_left
+  if (token.type === 'output') return token.trim_left || options.trim_value_left
+}
+
+function shouldTrimRight (token, inRaw, options) {
+  if (inRaw) return false
+  if (token.type === 'tag') return token.trim_right || options.trim_tag_right
+  if (token.type === 'output') return token.trim_right || options.trim_value_right
+}
+
+function trimLeft (token, greedy) {
+  if (!token || token.type !== 'html') return
+
+  const rLeft = greedy ? /\s+$/g : /[\t\r ]*$/g
+  token.value = token.value.replace(rLeft, '')
+}
+
+function trimRight (token, greedy) {
+  if (!token || token.type !== 'html') return
+
+  const rRight = greedy ? /^\s+/g : /^[\t\r ]*\n?/g
+  token.value = token.value.replace(rRight, '')
+}