mustache.js/mustache.js

/*!
 * mustache.js - Logic-less {{mustache}} templates with JavaScript
 * http://github.com/janl/mustache.js
 */
var Mustache = (typeof module !== "undefined" && module.exports) || {};

(function (exports) {

  exports.name = "mustache.js";
  exports.version = "0.5.1-dev";
  exports.tags = ["{{", "}}"];

  exports.parse = parse;
  exports.clearCache = clearCache;
  exports.compile = compile;
  exports.compilePartial = compilePartial;
  exports.render = render;

  exports.Scanner = Scanner;
  exports.Context = Context;
  exports.Renderer = Renderer;

  // This is here for backwards compatibility with 0.4.x.
  exports.to_html = function (template, view, partials, send) {
    var result = render(template, view, partials);

    if (typeof send === "function") {
      send(result);
    } else {
      return result;
    }
  };

  var whiteRe = /\s*/;
  var spaceRe = /\s+/;
  var nonSpaceRe = /\S/;
  var eqRe = /\s*=/;
  var curlyRe = /\s*\}/;
  var tagRe = /#|\^|\/|>|\{|&|=|!/;

  function isWhitespace(string) {
    return !nonSpaceRe.test(string);
  }

  var isArray = Array.isArray || function (obj) {
    return Object.prototype.toString.call(obj) === "[object Array]";
  };

  var quote = (typeof JSON !== "undefined" && JSON.stringify) || function (string) {
    return '"' + String(string).replace(/(^|[^\\])"/g, '\\"') + '"';
  };

  function escapeRe(string) {
    return string.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
  }

  var entityMap = {
    "&": "&",
    "<": "&lt;",
    ">": "&gt;",
    '"': '&quot;',
    "'": '&#39;'
  };

  function escapeHtml(string) {
    return String(string).replace(/&(?!\w+;)|[<>"']/g, function (s) {
      return entityMap[s];
    });
  }

  // Export these utility functions.
  exports.isWhitespace = isWhitespace;
  exports.isArray = isArray;
  exports.quote = quote;
  exports.escapeRe = escapeRe;
  exports.escapeHtml = escapeHtml;

  function Scanner(string) {
    this.string = string;
    this.tail = string;
    this.pos = 0;
  }

  /**
   * Returns `true` if the tail is empty (end of string).
   */
  Scanner.prototype.eos = function () {
    return this.tail === "";
  };

  /**
   * Tries to match the given regular expression at the current position.
   * Returns the matched text if it can match, `null` otherwise.
   */
  Scanner.prototype.scan = function (re) {
    var match = this.tail.match(re);

    if (match && match.index === 0) {
      this.tail = this.tail.substring(match[0].length);
      this.pos += match[0].length;
      return match[0];
    }

    return null;
  };

  /**
   * Skips all text until the given regular expression can be matched. Returns
   * the skipped string, which is the entire tail of this scanner if no match
   * can be made.
   */
  Scanner.prototype.scanUntil = function (re) {
    var match, pos = this.tail.search(re);

    switch (pos) {
    case -1:
      match = this.tail;
      this.pos += this.tail.length;
      this.tail = "";
      break;
    case 0:
      match = null;
      break;
    default:
      match = this.tail.substring(0, pos);
      this.tail = this.tail.substring(pos);
      this.pos += pos;
    }

    return match;
  };

  function Context(view, parent) {
    this.view = view;
    this.parent = parent;
    this.clearCache();
  }

  Context.make = function (view) {
    return (view instanceof Context) ? view : new Context(view);
  };

  Context.prototype.clearCache = function () {
    this._cache = {};
  };

  Context.prototype.push = function (view) {
    return new Context(view, this);
  };

  Context.prototype.lookup = function (name) {
    var value = this._cache[name];

    if (!value) {
      if (name === ".") {
        value = this.view;
      } else {
        var context = this;

        while (context) {
          if (name.indexOf(".") > 0) {
            var names = name.split("."), i = 0;

            value = context.view;

            while (value && i < names.length) {
              value = value[names[i++]];
            }
          } else {
            value = context.view[name];
          }

          if (value != null) {
            break;
          }

          context = context.parent;
        }
      }

      this._cache[name] = value;
    }

    if (typeof value === "function") {
      value = value.call(this.view);
    }

    return value;
  };

  function Renderer() {
    this.clearCache();
  }

  Renderer.prototype.clearCache = function () {
    this._cache = {};
    this._partialCache = {};
  };

  Renderer.prototype.compile = function (tokens, tags) {
    var fn = compileTokens(tokens),
        self = this;

    return function (view) {
      return fn(Context.make(view), self);
    };
  };

  Renderer.prototype.compilePartial = function (name, tokens, tags) {
    this._partialCache[name] = this.compile(tokens, tags);
    return this._partialCache[name];
  };

  Renderer.prototype.render = function (template, view) {
    var fn = this._cache[template];

    if (!fn) {
      fn = this.compile(template);
      this._cache[template] = fn;
    }

    return fn(view);
  };

  Renderer.prototype._section = function (name, context, callback) {
    var value = context.lookup(name);

    switch (typeof value) {
    case "object":
      if (isArray(value)) {
        var buffer = "";
        for (var i = 0, len = value.length; i < len; ++i) {
          buffer += callback(context.push(value[i]), this);
        }
        return buffer;
      } else {
        return callback(context.push(value), this);
      }
      break;
    case "function":
      var sectionText = callback(context, this), self = this;
      function scopedRender(template) {
        return self.render(template, context);
      }
      return value.call(context.view, sectionText, scopedRender) || "";
      break;
    default:
      if (value) {
        return callback(context, this);
      }
    }

    return "";
  };

  Renderer.prototype._inverted = function (name, context, callback) {
    var value = context.lookup(name);

    // From the spec: inverted sections may render text once based on the
    // inverse value of the key. That is, they will be rendered if the key
    // doesn't exist, is false, or is an empty list.
    if (value == null || value === false || (isArray(value) && value.length === 0)) {
      return callback(context, this);
    }

    return "";
  };

  Renderer.prototype._partial = function (name, context) {
    var fn = this._partialCache[name];

    if (fn) {
      return fn(context, this);
    }

    return "";
  };

  Renderer.prototype._name = function (name, context, escape) {
    var value = context.lookup(name);

    if (typeof value === "function") {
      value = value.call(context.view);
    }

    var string = (value == null) ? "" : String(value);

    if (escape) {
      return escapeHtml(string);
    }

    return string;
  };

  /**
   * Low-level function that compiles the given `tokens` into a
   * function that accepts two arguments: a Context and a
   * Renderer. Returns the body of the function as a string if
   * `returnBody` is true.
   */
  function compileTokens(tokens, returnBody) {
    if (typeof tokens === "string") {
      tokens = parse(tokens);
    }

    var body = ['""'];
    var token, method, escape;

    for (var i = 0, len = tokens.length; i < len; ++i) {
      token = tokens[i];

      switch (token.type) {
      case "#":
      case "^":
        method = (token.type === "#") ? "_section" : "_inverted";
        body.push("r." + method + "(" + quote(token.value) + ", c, function (c, r) {\n" +
          "  " + compileTokens(token.tokens, true) + "\n" +
          "})");
        break;
      case "{":
      case "&":
      case "name":
        escape = token.type === "name" ? "true" : "false";
        body.push("r._name(" + quote(token.value) + ", c, " + escape + ")");
        break;
      case ">":
        body.push("r._partial(" + quote(token.value) + ", c)");
        break;
      case "text":
        body.push(quote(token.value));
        break;
      }
    }

    // Convert to a string body.
    body = "return " + body.join(" + ") + ";";

    // Good for debugging.
    // console.log(body);

    if (returnBody) {
      return body;
    }

    // For great evil!
    return new Function("c, r", body);
  }

  function escapeTags(tags) {
    if (tags.length === 2) {
      return [
        new RegExp(escapeRe(tags[0]) + "\\s*"),
        new RegExp("\\s*" + escapeRe(tags[1]))
      ];
    }

    throw new Error("Invalid tags: " + tags.join(" "));
  }

  /**
   * Forms the given linear array of `tokens` into a nested tree structure
   * where tokens that represent a section have a "tokens" array property
   * that contains all tokens that are in that section.
   */
  function nestTokens(tokens) {
    var tree = [];
    var collector = tree;
    var sections = [];
    var token, section;

    for (var i = 0; i < tokens.length; ++i) {
      token = tokens[i];

      switch (token.type) {
      case "#":
      case "^":
        token.tokens = [];
        sections.push(token);
        collector.push(token);
        collector = token.tokens;
        break;
      case "/":
        if (sections.length === 0) {
          throw new Error("Unopened section: " + token.value);
        }

        section = sections.pop();

        if (section.value !== token.value) {
          throw new Error("Unclosed section: " + section.value);
        }

        if (sections.length > 0) {
          collector = sections[sections.length - 1].tokens;
        } else {
          collector = tree;
        }
        break;
      default:
        collector.push(token);
      }
    }

    // Make sure there were no open sections when we're done.
    section = sections.pop();

    if (section) {
      throw new Error("Unclosed section: " + section.value);
    }

    return tree;
  }

  /**
   * Combines the values of consecutive text tokens in the given `tokens` array
   * to a single token.
   */
  function squashTokens(tokens) {
    var lastToken;

    for (var i = 0; i < tokens.length; ++i) {
      token = tokens[i];

      if (lastToken && lastToken.type === "text" && token.type === "text") {
        lastToken.value += token.value;
        tokens.splice(i--, 1); // Remove this token from the array.
      } else {
        lastToken = token;
      }
    }
  }

  /**
   * Breaks up the given `template` string into a tree of token objects. If
   * `tags` is given here it must be an array with two string values: the
   * opening and closing tags used in the template (e.g. ["<%", "%>"]). Of
   * course, the default is to use mustaches (i.e. Mustache.tags).
   */
  function parse(template, tags) {
    tags = escapeTags(tags || exports.tags);

    var scanner = new Scanner(template);

    var tokens = [],      // Buffer to hold the tokens
        spaces = [],      // Indices of whitespace tokens on the current line
        hasTag = false,   // Is there a {{tag}} on the current line?
        nonSpace = false; // Is there a non-space char on the current line?

    // Strips all whitespace tokens array for the current line
    // if there was a {{#tag}} on it and otherwise only space.
    var stripSpace = function () {
      if (hasTag && !nonSpace) {
        while (spaces.length) {
          tokens.splice(spaces.pop(), 1);
        }
      } else {
        spaces = [];
      }

      hasTag = false;
      nonSpace = false;
    };

    var type, value, chr;

    while (!scanner.eos()) {
      value = scanner.scanUntil(tags[0]);

      if (value) {
        for (var i = 0, len = value.length; i < len; ++i) {
          chr = value[i];

          if (isWhitespace(chr)) {
            spaces.push(tokens.length);
          } else {
            nonSpace = true;
          }

          tokens.push({type: "text", value: chr});

          if (chr === "\n") {
            stripSpace(); // Check for whitespace on the current line.
          }
        }
      }

      // Match the opening tag.
      if (!scanner.scan(tags[0])) {
        break;
      }

      hasTag = true;
      type = scanner.scan(tagRe) || "name";

      // Skip any whitespace between tag and value.
      scanner.scan(whiteRe);

      // Extract the tag value.
      if (type === "=") {
        value = scanner.scanUntil(eqRe);
        scanner.scan(eqRe);
        scanner.scanUntil(tags[1]);
      } else if (type === "{") {
        value = scanner.scanUntil(curlyRe);
        scanner.scan(curlyRe);
        scanner.scanUntil(tags[1]);
      } else {
        value = scanner.scanUntil(tags[1]);
      }

      // Match the closing tag.
      if (!scanner.scan(tags[1])) {
        throw new Error("Unclosed tag at " + scanner.pos);
      }

      tokens.push({type: type, value: value});

      if (type === "name" || type === "{" || type === "&") {
        nonSpace = true;
      }

      // Set the tags for the next time around.
      if (type === "=") {
        tags = escapeTags(value.split(spaceRe));
      }
    }

    squashTokens(tokens);

    return nestTokens(tokens);
  }

  // The high-level clearCache, compile, compilePartial, and render functions
  // use this default renderer.
  var _renderer = new Renderer;

  /**
   * Clears all cached templates and partials.
   */
  function clearCache() {
    _renderer.clearCache();
  }

  /**
   * High-level API for compiling the given `tokens` down to a reusable
   * function. If `tokens` is a string it will be parsed using the given `tags`
   * before it is compiled.
   */
  function compile(tokens, tags) {
    return _renderer.compile(tokens, tags);
  }

  /**
   * High-level API for compiling the `tokens` for the partial with the given
   * `name` down to a reusable function. If `tokens` is a string it will be
   * parsed using the given `tags` before it is compiled.
   */
  function compilePartial(name, tokens, tags) {
    return _renderer.compilePartial(name, tokens, tags);
  }

  /**
   * High-level API for rendering the `template` using the given `view`. The
   * optional `partials` object may be given here for convenience, but note that
   * it will cause all partials to be re-compiled, thus hurting performance. Of
   * course, this only matters if you're going to render the same template more
   * than once. If so, it is best to call `compilePartial` before calling this
   * function and to leave the `partials` argument blank.
   */
  function render(template, view, partials) {
    if (partials) {
      for (var name in partials) {
        compilePartial(name, partials[name]);
      }
    }

    return _renderer.render(template, view);
  }

})(Mustache);