Add include support, with variables and the whole shebang

Fixes #462

1 files changed, 48 insertions, 0 deletions

diff --git a/lib/parse/include.js b/lib/parse/include.js
new file mode 100644
index 0000000..5fba2be
--- /dev/null
+++ b/lib/parse/include.js
@@ -0,0 +1,48 @@
+var _ = require('lodash');
+var fs = require('graceful-fs');
+var path = require('path');
+
+
+// Include helper
+function importInclude(name, paths) {
+    return paths
+    .map(function(folder) {
+        // Try including snippet from FS
+        try {
+            var fname = path.join(folder, name);
+            // Trim trailing newlines/space of imported snippets
+            return fs.readFileSync(fname, 'utf8').trimRight();
+        } catch(err) {}
+    })
+    .filter(Boolean)[0];
+}
+
+function includer(ctx, folders) {
+    return function(key) {
+        key = key.trim();
+        return ctx[key] || importInclude(key, folders);
+    };
+}
+
+module.exports = function(markdown, folder, ctx) {
+    // List of folders to search for includes
+    var folders = [];
+
+    // Handle folder arg (string or array)
+    if(_.isString(folder)) {
+        folders = [folder];
+    } else if(_.isArray(folder)) {
+        folders = folder;
+    }
+
+    // variable context
+    ctx = ctx || {};
+
+    // Memoized include function (to cache lookups)
+    var _include = _.memoize(includer(ctx, folders));
+
+    return markdown.replace(/{{([\s\S]+?)}}/g, function(match, key) {
+        // If fails leave content as is
+        return _include(key) || match;
+    });
+};