diff --git a/.gitattributes b/.gitattributes
index eb49e7815619..727f1cc68767 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1 +1,2 @@
 *.svelte linguist-language=HTML
+tsconfig*.json linguist-language=javascript
diff --git a/package.json b/package.json
index 9c1ca2b15b5a..8742fc27c67c 100644
--- a/package.json
+++ b/package.json
@@ -37,8 +37,8 @@
     "posttest": "agadoo internal/index.mjs",
     "prepublishOnly": "export PUBLISH=true && npm test && npm run create-stubs",
     "create-stubs": "node scripts/create-stubs.js",
-    "tsd": "tsc -p . --emitDeclarationOnly",
-    "typecheck": "tsc -p . --noEmit",
+    "tsd": "tsc -p src/compiler --emitDeclarationOnly && tsc -p src/runtime --emitDeclarationOnly",
+    "typecheck": "tsc -p src/compiler --noEmit && tsc -p src/runtime --noEmit",
     "lint": "eslint \"{src,test}/**/*.{ts,js}\""
   },
   "repository": {
diff --git a/src/compiler/compile/index.ts b/src/compiler/compile/index.ts
index 3f4a3eeb3225..f75a4390ec1e 100644
--- a/src/compiler/compile/index.ts
+++ b/src/compiler/compile/index.ts
@@ -1,4 +1,4 @@
-import { assign } from '../../runtime/internal/index';
+import { assign } from '../../runtime/internal/utils';
 import Stats from '../Stats';
 import parse from '../parse/index';
 import render_dom from './render-dom/index';
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
new file mode 100644
index 000000000000..7043efa7ddd1
--- /dev/null
+++ b/src/compiler/tsconfig.json
@@ -0,0 +1,11 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"include": ["."],
+
+	"compilerOptions": {
+		"lib": ["es2017", "webworker"]
+
+		// TODO: remove mocha types from the whole project
+		// "types": ["node", "estree"]
+	}
+}
diff --git a/src/runtime/internal/animations.ts b/src/runtime/internal/animations.ts
index 77c86aff0e3d..16aa4065552d 100644
--- a/src/runtime/internal/animations.ts
+++ b/src/runtime/internal/animations.ts
@@ -1,4 +1,5 @@
-import { identity as linear, noop, now } from './utils';
+import { identity as linear, noop } from './utils';
+import { now } from "./environment";
 import { loop } from './loop';
 import { create_rule, delete_rule } from './style_manager';
 import { AnimationConfig } from '../animate';
diff --git a/src/runtime/internal/environment.ts b/src/runtime/internal/environment.ts
new file mode 100644
index 000000000000..02cb05f30a19
--- /dev/null
+++ b/src/runtime/internal/environment.ts
@@ -0,0 +1,18 @@
+import { noop } from './utils';
+
+export const is_client = typeof window !== 'undefined';
+
+export let now: () => number = is_client
+	? () => window.performance.now()
+	: () => Date.now();
+
+export let raf = is_client ? requestAnimationFrame : noop;
+
+// used internally for testing
+export function set_now(fn) {
+	now = fn;
+}
+
+export function set_raf(fn) {
+	raf = fn;
+}
diff --git a/src/runtime/internal/index.ts b/src/runtime/internal/index.ts
index 6487f04525f3..d9d95541ebc3 100644
--- a/src/runtime/internal/index.ts
+++ b/src/runtime/internal/index.ts
@@ -1,6 +1,7 @@
 export * from './animations';
 export * from './await-block';
 export * from './dom';
+export * from './environment';
 export * from './keyed-each';
 export * from './lifecycle';
 export * from './loop';
diff --git a/src/runtime/internal/loop.ts b/src/runtime/internal/loop.ts
index cc6161105d48..0ab89d41351f 100644
--- a/src/runtime/internal/loop.ts
+++ b/src/runtime/internal/loop.ts
@@ -1,4 +1,4 @@
-import { now, raf } from './utils';
+import { now, raf } from "./environment";
 
 export interface Task { abort(): void; promise: Promise<void> }
 
diff --git a/src/runtime/internal/style_manager.ts b/src/runtime/internal/style_manager.ts
index 2721200627f2..ceb1b000eb53 100644
--- a/src/runtime/internal/style_manager.ts
+++ b/src/runtime/internal/style_manager.ts
@@ -1,5 +1,5 @@
 import { element } from './dom';
-import { raf } from './utils';
+import { raf } from "./environment";
 
 let stylesheet;
 let active = 0;
diff --git a/src/runtime/internal/transitions.ts b/src/runtime/internal/transitions.ts
index 5591ca1d5127..80c76ffec5d2 100644
--- a/src/runtime/internal/transitions.ts
+++ b/src/runtime/internal/transitions.ts
@@ -1,4 +1,5 @@
-import { identity as linear, is_function, noop, now, run_all } from './utils';
+import { identity as linear, is_function, noop, run_all } from './utils';
+import { now } from "./environment";
 import { loop } from './loop';
 import { create_rule, delete_rule } from './style_manager';
 import { custom_event } from './dom';
diff --git a/src/runtime/internal/utils.ts b/src/runtime/internal/utils.ts
index 152c0e79b02b..7fdf9591f49f 100644
--- a/src/runtime/internal/utils.ts
+++ b/src/runtime/internal/utils.ts
@@ -89,20 +89,3 @@ export function once(fn) {
 		fn.call(this, ...args);
 	}
 }
-
-const is_client = typeof window !== 'undefined';
-
-export let now: () => number = is_client
-	? () => window.performance.now()
-	: () => Date.now();
-
-export let raf = is_client ? requestAnimationFrame : noop;
-
-// used internally for testing
-export function set_now(fn) {
-	now = fn;
-}
-
-export function set_raf(fn) {
-	raf = fn;
-}
diff --git a/src/runtime/tsconfig.json b/src/runtime/tsconfig.json
new file mode 100644
index 000000000000..ed24bd727ef4
--- /dev/null
+++ b/src/runtime/tsconfig.json
@@ -0,0 +1,15 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"include": ["."],
+
+	"compilerOptions": {
+		"lib": ["es2015", "dom", "dom.iterable"],
+		"target": "es2015",
+		"types": [],
+
+		"baseUrl": ".",
+		"paths": {
+			"svelte/*": ["*"]
+		}
+	}
+}
diff --git a/test/tsconfig.json b/test/tsconfig.json
new file mode 100644
index 000000000000..61d7ba79ab2e
--- /dev/null
+++ b/test/tsconfig.json
@@ -0,0 +1,10 @@
+{
+	"extends": "../tsconfig.base.json",
+	"include": ["."],
+
+	"compilerOptions": {
+		"allowJs": true,
+		"checkJs": true,
+		"noEmit": true
+	}
+}
diff --git a/tsconfig.base.json b/tsconfig.base.json
new file mode 100644
index 000000000000..687cec479439
--- /dev/null
+++ b/tsconfig.base.json
@@ -0,0 +1,28 @@
+{
+	"compilerOptions": {
+		"rootDir": "src",
+
+		// target node v8+ (https://node.green/)
+		// the only missing feature is Array.prototype.values
+		"lib": ["es2017"],
+		"target": "es2017",
+
+		"declaration": true,
+		"declarationDir": "types",
+
+		"noEmitOnError": true,
+		"noErrorTruncation": true,
+
+		// rollup takes care of these
+		"module": "esnext",
+		"moduleResolution": "node",
+		"resolveJsonModule": true,
+		"allowSyntheticDefaultImports": true,
+
+		// TODO: error all the things
+		//"strict": true,
+		"noImplicitThis": true,
+		"noUnusedLocals": true,
+		"noUnusedParameters": true
+	}
+}
diff --git a/tsconfig.json b/tsconfig.json
deleted file mode 100644
index 07bc24acaf03..000000000000
--- a/tsconfig.json
+++ /dev/null
@@ -1,33 +0,0 @@
-{
-	"compilerOptions": {
-		"target": "es2015",
-		"module": "es6",
-		"declaration": true,
-		"declarationDir": "types",
-		"noImplicitThis": true,
-		"noUnusedLocals": true,
-		"noUnusedParameters": true,
-		"noEmitOnError": true,
-		"lib": [
-			"es5",
-			"es6",
-			"dom",
-			"es2015"
-		],
-		"importHelpers": true,
-		"moduleResolution": "node",
-		"baseUrl": ".",
-		"paths": {
-			"svelte/internal": ["./src/runtime/internal/index"],
-			"svelte/easing": ["./src/runtime/easing/index"],
-			"svelte/motion": ["./src/runtime/motion/index"],
-			"svelte/store": ["./src/runtime/store/index"]
-		},
-		"typeRoots": [
-			"node_modules/@types"
-		]
-	},
-	"include": [
-		"src/**/*"
-	]
-}