feat(index): scopes

Author: xakdog

lib/index.js

@@ -3,7 +3,7 @@ const merge = require('lodash.merge')
 const cloneDeep = require('lodash.clonedeep')
 const parseAndReplace = require('./expression_parser')
 
-let delimiters, unescapeDelimiters, delimiterRegex, unescapeDelimiterRegex, conditionals, loops, options
+let delimiters, unescapeDelimiters, delimiterRegex, unescapeDelimiterRegex, conditionals, loops, scopes, options
 
 module.exports = function PostHTMLExpressions (_options = {}) {
   options = _options
@@ -19,6 +19,7 @@ module.exports = function PostHTMLExpressions (_options = {}) {
 
   // conditional and loop options
   conditionals = options.conditionalTags || ['if', 'elseif', 'else']
+  scopes = options.scopeTags || ['scope']
   loops = options.loopTags || ['each']
 
   // kick off the parsing
@@ -60,7 +61,7 @@ function walk (opts, nodes) {
     }
 
     // if the node has content, recurse (unless it's a loop, handled later)
-    if (node.content && node.tag !== loops[0]) {
+    if (node.content && node.tag !== loops[0] && node.tag !== scopes[0]) {
       node.content = walk(opts, node.content)
     }
 
@@ -159,6 +160,27 @@ function walk (opts, nodes) {
       return m
     }
 
+    // parse scopes
+    if (node.tag === scopes[0]) {
+      console.log('scopes found')
+      // handle syntax error
+      if (!(node.attrs && node.attrs.with)) {
+        throw new Error(`the "${scopes[0]}" tag must have a "with" attribute`)
+      }
+
+      const target = vm.runInContext(node.attrs.with, ctx)
+
+      // handle additional syntax errors
+      if (typeof target !== 'object' || Array.isArray(target)) {
+        throw new Error('You must provide an object to make scope')
+      }
+
+      m.push(executeScoped(target, node))
+
+      // return directly out of the loop, which will skip the "each" tag
+      return m
+    }
+
     // return the node
     m.push(node)
     return m
@@ -248,10 +270,19 @@ function executeLoop (loopParams, p1, p2, node) {
   const scopedLocals = {}
   scopedLocals[loopParams[0]] = p1
   if (loopParams[1]) scopedLocals[loopParams[1]] = p2
+
+  return executeScoped(scopedLocals, node)
+}
+
+/**
+ * Runs walk function with arbitrary set of local variables
+ */
+function executeScoped (scopedLocals, node) {
   // merge nondestructively into existing locals
   const scopedOptions = merge(cloneDeep(options), { locals: scopedLocals })
   // walk through the contents and run replacements with modified options
   // we need to clone the node because the normal operation modifies
   // the node directly
   return walk(scopedOptions, cloneDeep(node.content))
 }
+