diff --git a/packages/string-templates/rollup.config.js b/packages/string-templates/rollup.config.js
index cb17fd893f..8b5f7a32e4 100644
--- a/packages/string-templates/rollup.config.js
+++ b/packages/string-templates/rollup.config.js
@@ -18,7 +18,7 @@ export default [
       file: "./dist/bundle.cjs",
     },
     plugins: [
-      typescript({ tsconfig: "tsconfig.build.json" }),
+      typescript({ tsconfig: "tsconfig.json" }),
       resolve({
         preferBuiltins: true,
         browser: true,
diff --git a/packages/string-templates/src/conversion/index.ts b/packages/string-templates/src/conversion/index.ts
index c6ec012ad9..1fb8d97467 100644
--- a/packages/string-templates/src/conversion/index.ts
+++ b/packages/string-templates/src/conversion/index.ts
@@ -114,7 +114,7 @@ export function convertHBSBlock(block, blockNumber) {
     const parts = splitBySpace(layer)
     if (value || parts.length > 1 || list[parts[0]]) {
       // first of layer should always be the helper
-      const helper = parts.splice(0, 1)
+      const [helper] = parts.splice(0, 1)
       if (list[helper]) {
         value = `helpers.${helper}(${buildList(parts, value)})`
       }
diff --git a/packages/string-templates/src/errors.ts b/packages/string-templates/src/errors.ts
index a0108d5018..79a8a525ef 100644
--- a/packages/string-templates/src/errors.ts
+++ b/packages/string-templates/src/errors.ts
@@ -1,7 +1,3 @@
 export class JsErrorTimeout extends Error {
   code = "ERR_SCRIPT_EXECUTION_TIMEOUT"
-
-  constructor() {
-    super()
-  }
 }
diff --git a/packages/string-templates/src/helpers/Helper.ts b/packages/string-templates/src/helpers/Helper.ts
index e7e7488c0f..e254b2086d 100644
--- a/packages/string-templates/src/helpers/Helper.ts
+++ b/packages/string-templates/src/helpers/Helper.ts
@@ -1,4 +1,8 @@
 export default class Helper {
+  private name
+  private fn
+  private useValueFallback
+
   constructor(name, fn, useValueFallback = true) {
     this.name = name
     this.fn = fn
diff --git a/packages/string-templates/src/helpers/date.ts b/packages/string-templates/src/helpers/date.ts
index 9d663573bd..70dc0bd617 100644
--- a/packages/string-templates/src/helpers/date.ts
+++ b/packages/string-templates/src/helpers/date.ts
@@ -1,12 +1,22 @@
 import dayjs from "dayjs"
-dayjs.extend(require("dayjs/plugin/duration"))
-dayjs.extend(require("dayjs/plugin/advancedFormat"))
-dayjs.extend(require("dayjs/plugin/isoWeek"))
-dayjs.extend(require("dayjs/plugin/weekYear"))
-dayjs.extend(require("dayjs/plugin/weekOfYear"))
-dayjs.extend(require("dayjs/plugin/relativeTime"))
-dayjs.extend(require("dayjs/plugin/utc"))
-dayjs.extend(require("dayjs/plugin/timezone"))
+
+import dayjsDurationPlugin from "dayjs/plugin/duration"
+import dayjsAdvancedFormatPlugin from "dayjs/plugin/advancedFormat"
+import dayjsIsoWeekPlugin from "dayjs/plugin/isoWeek"
+import dayjsWeekYearPlugin from "dayjs/plugin/weekYear"
+import dayjsWeekOfYearPlugin from "dayjs/plugin/weekOfYear"
+import dayjsRelativeTimePlugin from "dayjs/plugin/relativeTime"
+import dayjsUtcPlugin from "dayjs/plugin/utc"
+import dayjsTimezonePlugin from "dayjs/plugin/timezone"
+
+dayjs.extend(dayjsDurationPlugin)
+dayjs.extend(dayjsAdvancedFormatPlugin)
+dayjs.extend(dayjsIsoWeekPlugin)
+dayjs.extend(dayjsWeekYearPlugin)
+dayjs.extend(dayjsWeekOfYearPlugin)
+dayjs.extend(dayjsRelativeTimePlugin)
+dayjs.extend(dayjsUtcPlugin)
+dayjs.extend(dayjsTimezonePlugin)
 
 /**
  * This file was largely taken from the helper-date package - we did this for two reasons:
@@ -58,7 +68,7 @@ function getContext(thisArg, locals, options) {
   return context
 }
 
-function initialConfig(str, pattern, options) {
+function initialConfig(str, pattern, options = {}) {
   if (isOptions(pattern)) {
     options = pattern
     pattern = null
@@ -72,7 +82,7 @@ function initialConfig(str, pattern, options) {
   return { str, pattern, options }
 }
 
-function setLocale(str, pattern, options) {
+function setLocale(str, pattern, options = {}) {
   // if options is null then it'll get updated here
   const config = initialConfig(str, pattern, options)
   const defaults = { lang: "en", date: new Date(config.str) }
diff --git a/packages/string-templates/src/helpers/index.ts b/packages/string-templates/src/helpers/index.ts
index bad861567d..19d4ee3dff 100644
--- a/packages/string-templates/src/helpers/index.ts
+++ b/packages/string-templates/src/helpers/index.ts
@@ -44,8 +44,9 @@ const HELPERS = [
     if (value == null || typeof value !== "string") {
       return value == null ? "" : value
     }
-    if (value && value.string) {
-      value = value.string
+    // TODO: check, this should always be false
+    if (value && (value as any).string) {
+      value = (value as any).string
     }
     let text = value
     if (__opts && __opts.escapeNewlines) {
diff --git a/packages/string-templates/src/helpers/list.ts b/packages/string-templates/src/helpers/list.ts
index 8f08bc6f12..fde42b659a 100644
--- a/packages/string-templates/src/helpers/list.ts
+++ b/packages/string-templates/src/helpers/list.ts
@@ -1,7 +1,7 @@
 import { date, duration } from "./date"
 
 // https://github.com/evanw/esbuild/issues/56
-const externalCollections = {
+const externalCollections: Record<string, () => any> = {
   math: require("@budibase/handlebars-helpers/lib/math"),
   array: require("@budibase/handlebars-helpers/lib/array"),
   number: require("@budibase/handlebars-helpers/lib/number"),
diff --git a/packages/string-templates/src/processors/index.ts b/packages/string-templates/src/processors/index.ts
index a5bcf84eaf..7187bb6fd8 100644
--- a/packages/string-templates/src/processors/index.ts
+++ b/packages/string-templates/src/processors/index.ts
@@ -2,7 +2,7 @@ import { FIND_HBS_REGEX } from "../utilities"
 import * as preprocessor from "./preprocessor"
 import * as postprocessor from "./postprocessor"
 
-function process(output, processors, opts) {
+function process(output, processors, opts = {}) {
   for (let processor of processors) {
     // if a literal statement has occurred stop
     if (typeof output !== "string") {
diff --git a/packages/string-templates/src/processors/postprocessor.ts b/packages/string-templates/src/processors/postprocessor.ts
index 3122d43e53..39125b225a 100644
--- a/packages/string-templates/src/processors/postprocessor.ts
+++ b/packages/string-templates/src/processors/postprocessor.ts
@@ -6,6 +6,9 @@ export const PostProcessorNames = {
 
 /* eslint-disable no-unused-vars */
 class Postprocessor {
+  name
+  private fn
+
   constructor(name, fn) {
     this.name = name
     this.fn = fn
diff --git a/packages/string-templates/src/processors/preprocessor.ts b/packages/string-templates/src/processors/preprocessor.ts
index 39cfc07359..1fcbac629f 100644
--- a/packages/string-templates/src/processors/preprocessor.ts
+++ b/packages/string-templates/src/processors/preprocessor.ts
@@ -11,7 +11,7 @@ export const PreprocessorNames = {
 
 /* eslint-disable no-unused-vars */
 class Preprocessor {
-  private name: string
+  name: string
   private fn: any
 
   constructor(name, fn) {
diff --git a/packages/string-templates/src/utilities.ts b/packages/string-templates/src/utilities.ts
index 017f38db47..bcb9987c89 100644
--- a/packages/string-templates/src/utilities.ts
+++ b/packages/string-templates/src/utilities.ts
@@ -15,14 +15,14 @@ export const isJSAllowed = () => {
 // originally this could be done with a single regex using look behinds
 // but safari does not support this feature
 // original regex: /(?<!{){{[^{}]+}}(?!})/g
-export const findDoubleHbsInstances = string => {
+export const findDoubleHbsInstances = (string: string): string[] => {
   let copied = string
   const doubleRegex = new RegExp(FIND_HBS_REGEX)
   const regex = new RegExp(FIND_TRIPLE_HBS_REGEX)
   const tripleMatches = copied.match(regex)
   // remove triple braces
   if (tripleMatches) {
-    tripleMatches.forEach(match => {
+    tripleMatches.forEach((match: string) => {
       copied = copied.replace(match, "")
     })
   }
@@ -30,16 +30,21 @@ export const findDoubleHbsInstances = string => {
   return doubleMatches ? doubleMatches : []
 }
 
-export const isAlphaNumeric = char => {
+export const isAlphaNumeric = (char: string) => {
   return char.match(ALPHA_NUMERIC_REGEX)
 }
 
-export const swapStrings = (string, start, length, swap) => {
+export const swapStrings = (
+  string: string,
+  start: number,
+  length: number,
+  swap: string
+) => {
   return string.slice(0, start) + swap + string.slice(start + length)
 }
 
 export const removeHandlebarsStatements = (
-  string,
+  string: string,
   replacement = "Invalid binding"
 ) => {
   let regexp = new RegExp(FIND_HBS_REGEX)
@@ -54,10 +59,10 @@ export const removeHandlebarsStatements = (
   return string
 }
 
-export const btoa = plainText => {
+export const btoa = (plainText: string) => {
   return Buffer.from(plainText, "utf-8").toString("base64")
 }
 
-export const atob = base64 => {
+export const atob = (base64: string) => {
   return Buffer.from(base64, "base64").toString("utf-8")
 }
diff --git a/packages/string-templates/tsconfig.json b/packages/string-templates/tsconfig.json
index a7c7a0df67..52e3d78d20 100644
--- a/packages/string-templates/tsconfig.json
+++ b/packages/string-templates/tsconfig.json
@@ -1,6 +1,9 @@
 {
   "include": ["src/**/*"],
   "compilerOptions": {
+    "target": "es6",
+    "moduleResolution": "node",
+    "lib": ["dom"],
     "allowJs": true,
     "declaration": true,
     "emitDeclarationOnly": true,