Add utils.compile

lib/app/utils.js

@@ -91,3 +91,235 @@ export function getLocation (base) {
 export function urlJoin () {
   return [].slice.call(arguments).join('/').replace(/\/+/g, '/')
 }
+
+// Imported from path-to-regexp
+
+/**
+ * Compile a string to a template function for the path.
+ *
+ * @param  {string}             str
+ * @param  {Object=}            options
+ * @return {!function(Object=, Object=)}
+ */
+export function compile (str, options) {
+  return tokensToFunction(parse(str, options))
+}
+
+/**
+ * The main path matching regexp utility.
+ *
+ * @type {RegExp}
+ */
+const PATH_REGEXP = new RegExp([
+  // Match escaped characters that would otherwise appear in future matches.
+  // This allows the user to escape special characters that won't transform.
+  '(\\\\.)',
+  // Match Express-style parameters and un-named parameters with a prefix
+  // and optional suffixes. Matches appear as:
+  //
+  // "/:test(\\d+)?" => ["/", "test", "\d+", undefined, "?", undefined]
+  // "/route(\\d+)"  => [undefined, undefined, undefined, "\d+", undefined, undefined]
+  // "/*"            => ["/", undefined, undefined, undefined, undefined, "*"]
+  '([\\/.])?(?:(?:\\:(\\w+)(?:\\(((?:\\\\.|[^\\\\()])+)\\))?|\\(((?:\\\\.|[^\\\\()])+)\\))([+*?])?|(\\*))'
+].join('|'), 'g')
+
+/**
+ * Parse a string for the raw tokens.
+ *
+ * @param  {string}  str
+ * @param  {Object=} options
+ * @return {!Array}
+ */
+function parse (str, options) {
+  var tokens = []
+  var key = 0
+  var index = 0
+  var path = ''
+  var defaultDelimiter = options && options.delimiter || '/'
+  var res
+
+  while ((res = PATH_REGEXP.exec(str)) != null) {
+    var m = res[0]
+    var escaped = res[1]
+    var offset = res.index
+    path += str.slice(index, offset)
+    index = offset + m.length
+
+    // Ignore already escaped sequences.
+    if (escaped) {
+      path += escaped[1]
+      continue
+    }
+
+    var next = str[index]
+    var prefix = res[2]
+    var name = res[3]
+    var capture = res[4]
+    var group = res[5]
+    var modifier = res[6]
+    var asterisk = res[7]
+
+    // Push the current path onto the tokens.
+    if (path) {
+      tokens.push(path)
+      path = ''
+    }
+
+    var partial = prefix != null && next != null && next !== prefix
+    var repeat = modifier === '+' || modifier === '*'
+    var optional = modifier === '?' || modifier === '*'
+    var delimiter = res[2] || defaultDelimiter
+    var pattern = capture || group
+
+    tokens.push({
+      name: name || key++,
+      prefix: prefix || '',
+      delimiter: delimiter,
+      optional: optional,
+      repeat: repeat,
+      partial: partial,
+      asterisk: !!asterisk,
+      pattern: pattern ? escapeGroup(pattern) : (asterisk ? '.*' : '[^' + escapeString(delimiter) + ']+?')
+    })
+  }
+
+  // Match any characters still remaining.
+  if (index < str.length) {
+    path += str.substr(index)
+  }
+
+  // If the path exists, push it onto the end.
+  if (path) {
+    tokens.push(path)
+  }
+
+  return tokens
+}
+
+/**
+ * Prettier encoding of URI path segments.
+ *
+ * @param  {string}
+ * @return {string}
+ */
+function encodeURIComponentPretty (str) {
+  return encodeURI(str).replace(/[\/?#]/g, function (c) {
+    return '%' + c.charCodeAt(0).toString(16).toUpperCase()
+  })
+}
+
+/**
+ * Encode the asterisk parameter. Similar to `pretty`, but allows slashes.
+ *
+ * @param  {string}
+ * @return {string}
+ */
+function encodeAsterisk (str) {
+  return encodeURI(str).replace(/[?#]/g, function (c) {
+    return '%' + c.charCodeAt(0).toString(16).toUpperCase()
+  })
+}
+
+/**
+ * Expose a method for transforming tokens into the path function.
+ */
+function tokensToFunction (tokens) {
+  // Compile all the tokens into regexps.
+  var matches = new Array(tokens.length)
+
+  // Compile all the patterns before compilation.
+  for (var i = 0; i < tokens.length; i++) {
+    if (typeof tokens[i] === 'object') {
+      matches[i] = new RegExp('^(?:' + tokens[i].pattern + ')$')
+    }
+  }
+
+  return function (obj, opts) {
+    var path = ''
+    var data = obj || {}
+    var options = opts || {}
+    var encode = options.pretty ? encodeURIComponentPretty : encodeURIComponent
+
+    for (var i = 0; i < tokens.length; i++) {
+      var token = tokens[i]
+
+      if (typeof token === 'string') {
+        path += token
+
+        continue
+      }
+
+      var value = data[token.name]
+      var segment
+
+      if (value == null) {
+        if (token.optional) {
+          // Prepend partial segment prefixes.
+          if (token.partial) {
+            path += token.prefix
+          }
+
+          continue
+        } else {
+          throw new TypeError('Expected "' + token.name + '" to be defined')
+        }
+      }
+
+      if (Array.isArray(value)) {
+        if (!token.repeat) {
+          throw new TypeError('Expected "' + token.name + '" to not repeat, but received `' + JSON.stringify(value) + '`')
+        }
+
+        if (value.length === 0) {
+          if (token.optional) {
+            continue
+          } else {
+            throw new TypeError('Expected "' + token.name + '" to not be empty')
+          }
+        }
+
+        for (var j = 0; j < value.length; j++) {
+          segment = encode(value[j])
+
+          if (!matches[i].test(segment)) {
+            throw new TypeError('Expected all "' + token.name + '" to match "' + token.pattern + '", but received `' + JSON.stringify(segment) + '`')
+          }
+
+          path += (j === 0 ? token.prefix : token.delimiter) + segment
+        }
+
+        continue
+      }
+
+      segment = token.asterisk ? encodeAsterisk(value) : encode(value)
+
+      if (!matches[i].test(segment)) {
+        throw new TypeError('Expected "' + token.name + '" to match "' + token.pattern + '", but received "' + segment + '"')
+      }
+
+      path += token.prefix + segment
+    }
+
+    return path
+  }
+}
+
+/**
+ * Escape a regular expression string.
+ *
+ * @param  {string} str
+ * @return {string}
+ */
+function escapeString (str) {
+  return str.replace(/([.+*?=^!:${}()[\]|\/\\])/g, '\\$1')
+}
+
+/**
+ * Escape the capturing group by escaping special characters and meaning.
+ *
+ * @param  {string} group
+ * @return {string}
+ */
+function escapeGroup (group) {
+  return group.replace(/([=!:$\/()])/g, '\\$1')
+}