Add manifest (Level/community#83) (#79)

* Upgrade abstract-leveldown from ~6.1.0 to ~6.2.1
* Add manifest

deferred-leveldown.js

@@ -5,7 +5,16 @@ var deferrables = 'put get del batch clear'.split(' ')
 var optionalDeferrables = 'approximateSize compactRange'.split(' ')
 
 function DeferredLevelDOWN (db) {
-  AbstractLevelDOWN.call(this, '')
+  AbstractLevelDOWN.call(this, db.supports || {})
+
+  // TODO (future major): remove this fallback; db must have manifest that
+  // declares approximateSize and compactRange in additionalMethods.
+  optionalDeferrables.forEach(function (m) {
+    if (typeof db[m] === 'function' && !this.supports.additionalMethods[m]) {
+      this.supports.additionalMethods[m] = true
+    }
+  }, this)
+
   this._db = db
   this._operations = []
   closed(this)
@@ -51,11 +60,9 @@ function open (self) {
       return this._db[m].apply(this._db, arguments)
     }
   })
-  optionalDeferrables.forEach(function (m) {
-    if (typeof self._db[m] === 'function') {
-      self[m] = function () {
-        return this._db[m].apply(this._db, arguments)
-      }
+  Object.keys(self.supports.additionalMethods).forEach(function (m) {
+    self[m] = function () {
+      return this._db[m].apply(this._db, arguments)
     }
   })
 }
@@ -66,11 +73,9 @@ function closed (self) {
       this._operations.push({ method: m, args: arguments })
     }
   })
-  optionalDeferrables.forEach(function (m) {
-    if (typeof self._db[m] === 'function') {
-      self[m] = function () {
-        this._operations.push({ method: m, args: arguments })
-      }
+  Object.keys(self.supports.additionalMethods).forEach(function (m) {
+    self[m] = function () {
+      this._operations.push({ method: m, args: arguments })
     }
   })
   self._iterator = function (options) {

package.json

@@ -12,7 +12,7 @@
     "prepublishOnly": "npm run dependency-check"
   },
   "dependencies": {
-    "abstract-leveldown": "~6.1.0",
+    "abstract-leveldown": "~6.2.1",
     "inherits": "^2.0.3"
   },
   "devDependencies": {