Add yaml support

README.md

@@ -10,8 +10,8 @@ We also support JSONata Notebooks. They are automatically activated for files wi
 
 Within notebooks several additional functions are available:
 
-- `$parseString($content[, $type])` takes up to two arguments. It parses `$content` into an JSON object. This happens based on the variable `$type` with a JSON or an XML parser. JSON is the default parser.
-- `$loadFile($file[, $type])` takes up to two arguments. `$file` represents the filename to be loaded. With the optional argument `$type` one can specify how this file should be loaded. At the moment only `json` and `xml` can be chosen whereas json is the standard if `$type` is missing.
+- `$parseString($content[, $type])` takes up to two arguments. It parses `$content` into an JSON object. This happens based on the variable `$type` with a JSON, XML or YAML parser. JSON is the default parser.
+- `$loadFile($file[, $type])` takes up to two arguments. `$file` represents the filename to be loaded. With the optional argument `$type` one can specify how this file should be loaded. At the moment only `json`, `xml` and `yaml` can be chosen whereas json is the standard if `$type` is missing.
 - `$loadUrl($url[, $type])` works just like `$loadFile()` but with URLs instead of files.
 
 - `$readFile($file)` reads a file and returns the result as a string.

package.json

@@ -85,6 +85,7 @@
   },
   "dependencies": {
     "@types/lodash": "^4.14.178",
+    "js-yaml": "^4.1.0",
     "json-stringify-safe": "^5.0.1",
     "jsonata": "^2.0.3",
     "lodash": "^4.17.21",

src/kernel/functions.ts

@@ -5,6 +5,7 @@ import { Utils } from 'vscode-uri';
 import fetch from 'node-fetch';
 import loadJSON from './loader/json';
 import loadXML from './loader/xml';
+import loadYaml from './loader/yaml';
 
 const jsonata = require('jsonata');
 
@@ -22,6 +23,8 @@ export function parseString(content: string, type?: string) {
     return loadJSON(content);
   } if (type === 'xml') {
     return loadXML(content);
+  } if (type === 'yaml') {
+    return loadYaml(content)
   }
   return Promise.reject('unknown file handler!');
 }
@@ -53,6 +56,11 @@ export function readUrl(url: string) {
 }
 
 export function loadFile(filename: string, type?: string) {
+  if (!type && filename.endsWith(".xml")) {
+    type = "xml"
+  } else if (!type && (filename.endsWith("yaml") || filename.endsWith("yml"))) {
+    type = "yaml"
+  }
   return readFile(filename)
     .then((content) => parseString(content, type));
 }

src/kernel/loader/yaml.ts

@@ -0,0 +1,9 @@
+const yaml = require('js-yaml');
+
+export default function loadYaml(fileString: string) : Promise<unknown> {
+     try {
+        return Promise.resolve(yaml.load(fileString));
+    } catch(e) {
+        return Promise.reject(e);
+    }
+}