1 files changed, 49 insertions, 1 deletions
diff --git a/api/services/zmk/keymap.js b/api/services/zmk/keymap.js
index a8837ea..4eafb88 100644
--- a/api/services/zmk/keymap.js
+++ b/api/services/zmk/keymap.js
@@ -9,6 +9,14 @@ const uniq = require('lodash/uniq')
 
 const { renderTable } = require('./layout')
 
+class KeymapValidationError extends Error {
+  constructor (errors) {
+    super()
+    this.name = 'KeymapValidationError'
+    this.errors = errors
+  }
+}
+
 const behaviours = JSON.parse(fs.readFileSync(path.join(__dirname, 'data/zmk-behaviors.json')))
 const behavioursByBind = keyBy(behaviours, 'code')
 
@@ -145,8 +153,48 @@ function generateKeymapJSON (layout, keymap, encoded) {
   return base.replace('"layers": null', `"layers": [\n    ${layers.join(', ')}\n  ]`)
 }
 
+function validateKeymapJson(keymap) {
+  const errors = []
+
+  if (typeof keymap !== 'object' || keymap === null) {
+    errors.push('keymap.json root must be an object')
+  } else if (!Array.isArray(keymap.layers)) {
+    errors.push('keymap must include "layers" array')
+  } else {
+    for (let i in keymap.layers) {
+      const layer = keymap.layers[i]
+
+      if (!Array.isArray(layer)) {
+        errors.push(`Layer at layers[${i}] must be an array`)
+      } else {
+        for (let j in layer) {
+          const key = layer[j]
+          const keyPath = `layers[${i}][${j}]`
+
+          if (typeof key !== 'string') {
+            errors.push(`Value at "${keyPath}" must be a string`)
+          } else {
+            const bind = key.match(/^&.+?\b/)
+            if (!(bind && bind[0] in behavioursByBind)) {
+              errors.push(`Key bind at "${keyPath}" has invalid behaviour`)
+            }
+          }
+
+          // TODO: validate remaining bind parameters
+        }
+      }
+    }
+  }
+
+  if (errors.length) {
+    throw new KeymapValidationError(errors)
+  }
+}
+
 module.exports = {
+  KeymapValidationError,
   encodeKeymap,
   parseKeymap,
-  generateKeymap
+  generateKeymap,
+  validateKeymapJson
 }