diff --git a/codegen/common.ts b/codegen/common.ts
index c2517ff..bd67143 100644
--- a/codegen/common.ts
+++ b/codegen/common.ts
@@ -1,12 +1,12 @@
-export interface CodeGenSpec extends CommonSpec {
-    operators: PartialOperatorSpec[];
-}
-
 export interface CommonSpec {
     minExponent: number;
     maxExponent: number;
 }
 
+export interface CodeGenSpec extends CommonSpec {
+    operators: PartialOperatorSpec[];
+}
+
 export interface PartialOperatorSpec {
     fileNamePrefix: string;
     uncurriedTypeNamePrefix: string;
@@ -53,7 +53,7 @@ function genImport({ symbols, source }: ImportSpec): string {
     return `import { ${symbols.join(", ")} } from "${source}";`;
 }
 
-function order(first: string, second: string) {
+function order(first: string, second: string): number {
     if (first < second) {
         return -1;
     }
@@ -63,7 +63,7 @@ function order(first: string, second: string) {
     return 0;
 }
 
-export function genUncurriedTypeName(spec: OperatorSpec, left?: string | number, right?: string | number) {
+export function genUncurriedTypeName(spec: OperatorSpec, left?: string | number, right?: string | number): string {
     const args = left !== undefined && right !== undefined ? `<${left}, ${right}>` : "";
     return `${spec.uncurriedTypeNamePrefix}Exponents${args}`;
 }
@@ -76,6 +76,6 @@ export function genValueName(value: number): string {
     return `${sign}${Math.abs(value)}`;
 }
 
-export function indent(line: string) {
+export function indent(line: string): string {
     return "    " + line;
 }
diff --git a/codegen/emit.ts b/codegen/emit.ts
index e369dca..b20e701 100644
--- a/codegen/emit.ts
+++ b/codegen/emit.ts
@@ -12,7 +12,7 @@ export interface EmitPlan {
     source: string;
 }
 
-export function emit(callback?: () => void) {
+export function emit(callback?: () => void): void {
     const emits: EmitPlan[] = getEmitPlans();
     prepForEmit(() => {
         let index = -1;
@@ -39,11 +39,11 @@ export function getEmitPlans(): EmitPlan[] {
     return emits;
 }
 
-function prepForEmit(callback: () => void) {
+function prepForEmit(callback: () => void): void {
     makeDirectory(PATH_PREFIX, () => makeDirectory(TEST_PREFIX, callback));
 }
 
-function makeDirectory(path: string, callback: () => void) {
+function makeDirectory(path: string, callback: () => void): void {
     exists(path, doesExist => {
         if (doesExist) {
             return callback();
@@ -58,7 +58,7 @@ function makeDirectory(path: string, callback: () => void) {
     });
 }
 
-function emitFile({ path, source }: EmitPlan, callback?: () => void) {
+function emitFile({ path, source }: EmitPlan, callback?: () => void): void {
     writeFile(path, source, error => {
         if (error) {
             console.error(`There was an error writing to ${path}`);
diff --git a/codegen/genTests.ts b/codegen/genTests.ts
index 1d52321..2313397 100644
--- a/codegen/genTests.ts
+++ b/codegen/genTests.ts
@@ -55,6 +55,6 @@ function genErrorTest(spec: OperatorSpec, left: number, right: number): string[]
     ];
 }
 
-function genTestBaseName(spec: OperatorSpec, left: number, right: number) {
+function genTestBaseName(spec: OperatorSpec, left: number, right: number): string {
     return `${spec.testTypeNamePrefix}Of${genValueName(left)}And${genValueName(right)}`;
 }
diff --git a/codegen/genTypes.ts b/codegen/genTypes.ts
index 5677a90..c672d9e 100644
--- a/codegen/genTypes.ts
+++ b/codegen/genTypes.ts
@@ -62,6 +62,6 @@ function genCurriedTypeName({ curriedTypeNamePrefix }: OperatorSpec, value: numb
     return `${curriedTypeNamePrefix}${genValueName(value)}`;
 }
 
-function genErrorCase() {
+function genErrorCase(): string {
     return indent(": ArithmeticError;");
 }
diff --git a/package.json b/package.json
index a8d24f6..d347e0b 100644
--- a/package.json
+++ b/package.json
@@ -22,10 +22,11 @@
     "scripts": {
         "build": "npm-run-all -s codegen compile:src",
         "codegen": "npm-run-all -s compile:codegen node:codegen",
-        "compile:src": "tsc -p src",
         "compile:codegen": "tsc -p codegen",
-        "lint": "tslint -p src/tsconfig.json -c tslint.json '{src,codegen}/**/*.ts'",
-        "lint:fix": "yarn lint --fix",
+        "compile:src": "tsc -p src",
+        "lint:codegen": "tslint -p codegen/tsconfig.json -c tslint.json",
+        "lint:src": "tslint -p src/tsconfig.json -c tslint.json",
+        "lint": "npm-run-all -p lint:codegen lint:src",
         "node:codegen": "node codegen/dist/emit",
         "test": "jest --config jest.config.json",
         "prepack": "yarn build",