Convert db module to typescript

Also had to change config module to bind `.this` value, due to
differences in setup.

Change-type: patch
Signed-off-by: Cameron Diver <cameron@resin.io>

package.json

@@ -24,6 +24,7 @@
   },
   "devDependencies": {
     "@types/bluebird": "^3.5.20",
+    "@types/knex": "^0.14.14",
     "@types/lodash": "^4.14.109",
     "@types/mz": "0.0.32",
     "@types/node": "^10.3.1",

src/config.coffee

@@ -267,7 +267,7 @@ module.exports = class Config extends EventEmitter
 		@set({ uuid, deviceApiKey })
 
 	get: (key, trx) =>
-		db = trx ? @db.models
+		db = trx ? @db.models.bind(@db)
 		# Get value for "key" from config.json or db
 		Promise.try =>
 			switch @schema[key]?.source

src/db.coffee

@@ -1,33 +0,0 @@
-Knex = require 'knex'
-path = require 'path'
-constants = require './lib/constants'
-
-module.exports = class DB
-	constructor: ({ @databasePath } = {}) ->
-		@databasePath ?= constants.databasePath
-		@knex = Knex(
-			client: 'sqlite3'
-			connection:
-				filename: @databasePath
-			useNullAsDefault: true
-		)
-
-	init: =>
-		@knex('knex_migrations_lock').update({ is_locked: 0 })
-		.catch(->) # Knex doesn't return a bluebird promise here so we can't catchReturn :(
-		.then =>
-			@knex.migrate.latest(directory: path.join(__dirname, 'migrations'))
-
-	# Returns a knex object for one of the models (tables)
-	models: (modelName) =>
-		@knex(modelName)
-
-	upsertModel: (modelName, obj, id, trx) =>
-		knex = trx ? @knex
-		knex(modelName).update(obj).where(id)
-		.then (n) ->
-			if n == 0
-				knex(modelName).insert(obj)
-
-	transaction: (cb) =>
-		@knex.transaction(cb)

src/db.ts

@@ -0,0 +1,66 @@
+import * as Bluebird from 'bluebird';
+import * as Knex from 'knex';
+import * as path from 'path';
+
+import * as constants from './lib/constants';
+
+interface DBOpts {
+	databasePath?: string;
+}
+
+type DBTransactionCallback = (trx: Knex.Transaction) => void;
+
+class DB {
+	private databasePath: string;
+	private knex: Knex;
+
+	public constructor({ databasePath }: DBOpts = {}) {
+		this.databasePath = databasePath || constants.databasePath;
+		this.knex = Knex({
+			client: 'sqlite3',
+			connection: {
+				filename: this.databasePath,
+			},
+			useNullAsDefault: true,
+		});
+
+	}
+
+	public init(): Bluebird<void> {
+		return this.knex('knex_migrations_lock').update({ is_locked: 0})
+			.catch(() => { return; })
+			.then(() => {
+				return this.knex.migrate.latest({
+					directory: path.join(__dirname, 'migrations'),
+				});
+			});
+	}
+
+	public models(modelName: string): Knex.QueryBuilder {
+		return this.knex(modelName);
+	}
+
+	public upsertModel(
+		modelName: string,
+		obj: any,
+		id: number | { [key: string]: string},
+		trx?: Knex.Transaction,
+	): Bluebird<any> {
+
+		const knex = trx || this.knex;
+
+		return knex(modelName).update(obj).where(id)
+			.then((n: number) => {
+				if (n === 0) {
+					return knex(modelName).insert(obj);
+				}
+			});
+	}
+
+	public transaction(cb: DBTransactionCallback): Bluebird<Knex.Transaction> {
+		return this.knex.transaction(cb);
+	}
+
+}
+
+export = DB;