refactoring

packages/suggestion/src/findSuggestionMatch.ts

@@ -0,0 +1,82 @@
+import { ResolvedPos } from 'prosemirror-model'
+
+export interface Trigger {
+  char: string,
+  allowSpaces: boolean,
+  startOfLine: boolean,
+  $position: ResolvedPos,
+}
+
+export type SuggestionMatch = {
+  range: {
+    from: number,
+    to: number,
+  },
+  query: string,
+  text: string,
+} | null
+
+export function findSuggestionMatch(config: Trigger): SuggestionMatch {
+  const {
+    char, allowSpaces, startOfLine, $position,
+  } = config
+
+  // cancel if top level node
+  if ($position.depth <= 0) {
+    return null
+  }
+
+  // Matching expressions used for later
+  const escapedChar = `\\${char}`
+  const suffix = new RegExp(`\\s${escapedChar}$`)
+  const prefix = startOfLine ? '^' : ''
+  const regexp = allowSpaces
+    ? new RegExp(`${prefix}${escapedChar}.*?(?=\\s${escapedChar}|$)`, 'gm')
+    : new RegExp(`${prefix}(?:^)?${escapedChar}[^\\s${escapedChar}]*`, 'gm')
+
+  // Lookup the boundaries of the current node
+  const textFrom = $position.before()
+
+  // Only look up to the cursor, old behavior: textTo = $position.end()
+  const textTo = $position.pos
+
+  const text = $position.doc.textBetween(textFrom, textTo, '\0', '\0')
+
+  let match = regexp.exec(text)
+  let position = null
+
+  while (match !== null) {
+    // JavaScript doesn't have lookbehinds; this hacks a check that first character is " "
+    // or the line beginning
+    const matchPrefix = match.input.slice(Math.max(0, match.index - 1), match.index)
+
+    if (/^[\s\0]?$/.test(matchPrefix)) {
+      // The absolute position of the match in the document
+      const from = match.index + $position.start()
+      let to = from + match[0].length
+
+      // Edge case handling; if spaces are allowed and we're directly in between
+      // two triggers
+      if (allowSpaces && suffix.test(text.slice(to - 1, to + 1))) {
+        match[0] += ' '
+        to += 1
+      }
+
+      // If the $position is located within the matched substring, return that range
+      if (from < $position.pos && to >= $position.pos) {
+        position = {
+          range: {
+            from,
+            to,
+          },
+          query: match[0].slice(char.length),
+          text: match[0],
+        }
+      }
+    }
+
+    match = regexp.exec(text)
+  }
+
+  return position
+}