feat: add trans_choice() method.

Author: xiCO2k

src/index.ts

@@ -2,6 +2,7 @@ import { reactive, Plugin } from 'vue'
 import { OptionsInterface } from './interfaces/options'
 import { LanguageInterface } from './interfaces/language'
 import { ReplacementsInterface } from './interfaces/replacements'
+import { choose } from './pluralization'
 
 /**
  * The Default language will be used if there is no lang provided.
@@ -70,13 +71,29 @@ export function loadLanguageAsync(lang: string): Promise<string | void> {
 /**
  * Get the translation for the given key.
  */
-export function trans(key: string, replacements?: ReplacementsInterface): string {
+export function trans(key: string, replacements: ReplacementsInterface = {}): string {
   if (!activeMessages[key]) {
     activeMessages[key] = key
   }
 
-  let message = activeMessages[key]
+  return makeReplacements(activeMessages[key], replacements)
+}
+
+/**
+ * Translates the given message based on a count.
+ */
+export function trans_choice(key: string, number: number, replacements: ReplacementsInterface = {}): string {
+  const message = trans(key, replacements)
+
+  replacements.count = number.toString()
 
+  return makeReplacements(choose(message, number, options.lang), replacements)
+}
+
+/**
+ * Make the place-holder replacements on a line.
+ */
+function makeReplacements(message: string, replacements?: ReplacementsInterface): string {
   const capitalize = (s) => s.charAt(0).toUpperCase() + s.slice(1)
 
   Object.entries(replacements || []).forEach(([key, value]) => {

src/pluralization.ts

@@ -0,0 +1,71 @@
+import { getPluralIndex } from './utils/get-plural-index'
+
+/**
+ * Select a proper translation string based on the given number.
+ */
+export function choose(message: string, number: number, lang: string): string {
+  let segments = message.split('|')
+  const extracted = extract(segments, number)
+
+  if (extracted !== null) {
+    return extracted.trim()
+  }
+
+  segments = stripConditions(segments)
+  const pluralIndex = getPluralIndex(lang, number)
+
+  if (segments.length === 1 || !segments[pluralIndex]) {
+    return segments[0]
+  }
+
+  return segments[pluralIndex]
+}
+
+/**
+ * Extract a translation string using inline conditions.
+ */
+function extract(segments: string[], number: number): string | null {
+  for (const part of segments) {
+    let line = extractFromString(part, number)
+
+    if (line !== null) {
+      return line
+    }
+  }
+
+  return null
+}
+
+/**
+ * Get the translation string if the condition matches.
+ */
+function extractFromString(part: string, number: number): string | null {
+  const matches = part.match(/^[\{\[]([^\[\]\{\}]*)[\}\]](.*)/s) || []
+  if (matches.length !== 3) {
+    return null
+  }
+
+  const condition = matches[1]
+  const value = matches[2]
+
+  if (condition.includes(',')) {
+    let [from, to] = condition.split(',')
+
+    if (to === '*' && number >= parseFloat(from)) {
+      return value
+    } else if (from === '*' && number <= parseFloat(to)) {
+      return value
+    } else if (number >= parseFloat(from) && number <= parseFloat(to)) {
+      return value
+    }
+  }
+
+  return parseFloat(condition) === number ? value : null
+}
+
+/**
+ * Strip the inline conditions from each segment, just leaving the text.
+ */
+function stripConditions(segments: string[]): string[] {
+  return segments.map((part) => part.replace(/^[\{\[]([^\[\]\{\}]*)[\}\]]/, ''))
+}