File: template/js/template-micro.js
- /*jshint expr:true */
-
- /**
- Adds the `Y.Template.Micro` template engine, which provides fast, simple
- string-based micro-templating similar to ERB or Underscore templates.
-
- @module template
- @submodule template-micro
- @since 3.8.0
- **/
-
- /**
- Fast, simple string-based micro-templating engine similar to ERB or Underscore
- templates.
-
- @class Template.Micro
- @static
- @since 3.8.0
- **/
-
- // This code was heavily inspired by Underscore.js's _.template() method
- // (written by Jeremy Ashkenas), which was in turn inspired by John Resig's
- // micro-templating implementation.
-
- var Micro = Y.namespace('Template.Micro');
-
- /**
- Default options for `Y.Template.Micro`.
-
- @property {Object} options
-
- @param {RegExp} [options.code] Regex that matches code blocks like
- `<% ... %>`.
- @param {RegExp} [options.escapedOutput] Regex that matches escaped output
- tags like `<%= ... %>`.
- @param {RegExp} [options.rawOutput] Regex that matches raw output tags like
- `<%== ... %>`.
- @param {RegExp} [options.stringEscape] Regex that matches characters that
- need to be escaped inside single-quoted JavaScript string literals.
- @param {Object} [options.stringReplace] Hash that maps characters matched by
- `stringEscape` to the strings they should be replaced with. If you add
- a character to the `stringEscape` regex, you need to add it here too or
- it will be replaced with an empty string.
-
- @static
- @since 3.8.0
- **/
- Micro.options = {
- code : /<%([\s\S]+?)%>/g,
- escapedOutput: /<%=([\s\S]+?)%>/g,
- rawOutput : /<%==([\s\S]+?)%>/g,
- stringEscape : /\\|'|\r|\n|\t|\u2028|\u2029/g,
-
- stringReplace: {
- '\\' : '\\\\',
- "'" : "\\'",
- '\r' : '\\r',
- '\n' : '\\n',
- '\t' : '\\t',
- '\u2028': '\\u2028',
- '\u2029': '\\u2029'
- }
- };
-
- /**
- Compiles a template string into a JavaScript function. Pass a data object to the
- function to render the template using the given data and get back a rendered
- string.
-
- Within a template, use `<%= ... %>` to output the value of an expression (where
- `...` is the JavaScript expression or data variable to evaluate). The output
- will be HTML-escaped by default. To output a raw value without escaping, use
- `<%== ... %>`, but be careful not to do this with untrusted user input.
-
- To execute arbitrary JavaScript code within the template without rendering its
- output, use `<% ... %>`, where `...` is the code to be executed. This allows the
- use of if/else blocks, loops, function calls, etc., although it's recommended
- that you avoid embedding anything beyond basic flow control logic in your
- templates.
-
- Properties of the data object passed to a template function are made available
- on a `data` variable within the scope of the template. So, if you pass in
- the object `{message: 'hello!'}`, you can print the value of the `message`
- property using `<%= data.message %>`.
-
- @example
-
- YUI().use('template-micro', function (Y) {
- var template = '<ul class="<%= data.classNames.list %>">' +
- '<% Y.Array.each(data.items, function (item) { %>' +
- '<li><%= item %></li>' +
- '<% }); %>' +
- '</ul>';
-
- // Compile the template into a function.
- var compiled = Y.Template.Micro.compile(template);
-
- // Render the template to HTML, passing in the data to use.
- var html = compiled({
- classNames: {list: 'demo'},
- items : ['one', 'two', 'three', 'four']
- });
- });
-
- @method compile
- @param {String} text Template text to compile.
- @param {Object} [options] Options. If specified, these options will override the
- default options defined in `Y.Template.Micro.options`. See the documentation
- for that property for details on which options are available.
- @return {Function} Compiled template function. Execute this function and pass in
- a data object to render the template with the given data.
- @static
- @since 3.8.0
- **/
- Micro.compile = function (text, options) {
- /*jshint evil:true */
-
- var blocks = [],
- tokenClose = "\uffff",
- tokenOpen = "\ufffe",
- source;
-
- options = Y.merge(Micro.options, options);
-
- // Parse the input text into a string of JavaScript code, with placeholders
- // for code blocks. Text outside of code blocks will be escaped for safe
- // usage within a double-quoted string literal.
- //
- // $b is a blank string, used to avoid creating lots of string objects.
- //
- // $v is a function that returns the supplied value if the value is truthy
- // or the number 0, or returns an empty string if the value is falsy and not
- // 0.
- //
- // $t is the template string.
- source = "var $b='', $v=function (v){return v || v === 0 ? v : $b;}, $t='" +
-
- // U+FFFE and U+FFFF are guaranteed to represent non-characters, so no
- // valid UTF-8 string should ever contain them. That means we can freely
- // strip them out of the input text (just to be safe) and then use them
- // for our own nefarious purposes as token placeholders!
- //
- // See http://en.wikipedia.org/wiki/Mapping_of_Unicode_characters#Noncharacters
- text.replace(/\ufffe|\uffff/g, '')
-
- .replace(options.rawOutput, function (match, code) {
- return tokenOpen + (blocks.push("'+\n$v(" + code + ")+\n'") - 1) + tokenClose;
- })
-
- .replace(options.escapedOutput, function (match, code) {
- return tokenOpen + (blocks.push("'+\n$e($v(" + code + "))+\n'") - 1) + tokenClose;
- })
-
- .replace(options.code, function (match, code) {
- return tokenOpen + (blocks.push("';\n" + code + "\n$t+='") - 1) + tokenClose;
- })
-
- .replace(options.stringEscape, function (match) {
- return options.stringReplace[match] || '';
- })
-
- // Replace the token placeholders with code.
- .replace(/\ufffe(\d+)\uffff/g, function (match, index) {
- return blocks[parseInt(index, 10)];
- })
-
- // Remove noop string concatenations that have been left behind.
- .replace(/\n\$t\+='';\n/g, '\n') +
-
- "';\nreturn $t;";
-
- // If compile() was called from precompile(), return precompiled source.
- if (options.precompile) {
- return "function (Y, $e, data) {\n" + source + "\n}";
- }
-
- // Otherwise, return an executable function.
- return this.revive(new Function('Y', '$e', 'data', source));
- };
-
- /**
- Precompiles the given template text into a string of JavaScript source code that
- can be evaluated later in another context (or on another machine) to render the
- template.
-
- A common use case is to precompile templates at build time or on the server,
- then evaluate the code on the client to render a template. The client only needs
- to revive and render the template, avoiding the work of the compilation step.
-
- @method precompile
- @param {String} text Template text to precompile.
- @param {Object} [options] Options. If specified, these options will override the
- default options defined in `Y.Template.Micro.options`. See the documentation
- for that property for details on which options are available.
- @return {String} Source code for the precompiled template.
- @static
- @since 3.8.0
- **/
- Micro.precompile = function (text, options) {
- options || (options = {});
- options.precompile = true;
-
- return this.compile(text, options);
- };
-
- /**
- Compiles and renders the given template text in a single step.
-
- This can be useful for single-use templates, but if you plan to render the same
- template multiple times, it's much better to use `compile()` to compile it once,
- then simply call the compiled function multiple times to avoid recompiling.
-
- @method render
- @param {String} text Template text to render.
- @param {Object} data Data to pass to the template.
- @param {Object} [options] Options. If specified, these options will override the
- default options defined in `Y.Template.Micro.options`. See the documentation
- for that property for details on which options are available.
- @return {String} Rendered result.
- @static
- @since 3.8.0
- **/
- Micro.render = function (text, data, options) {
- return this.compile(text, options)(data);
- };
-
- /**
- Revives a precompiled template function into a normal compiled template function
- that can be called to render the template. The precompiled function must already
- have been evaluated to a function -- you can't pass raw JavaScript code to
- `revive()`.
-
- @method revive
- @param {Function} precompiled Precompiled template function.
- @return {Function} Revived template function, ready to be rendered.
- @static
- @since 3.8.0
- **/
- Micro.revive = function (precompiled) {
- return function (data) {
- data || (data = {});
- return precompiled.call(data, Y, Y.Escape.html, data);
- };
- };
-
-