diff --git a/src/tiny-invariant.flow.js b/src/tiny-invariant.flow.js
index 0f534cc..a8175c8 100644
--- a/src/tiny-invariant.flow.js
+++ b/src/tiny-invariant.flow.js
@@ -4,6 +4,23 @@
 
 const prefix: string = 'Invariant failed';
 
+/**
+ * __invariant__
+ * 
+ * The `invariant` function takes a value, and if the value is falsy then the `invariant` function will throw. If the value is truthy, then the function will not throw.
+ *
+ * @param {boolean} condition A boolean condition - if falsey will thrown an error.
+ * @param {(string|() => string)} message The message provided to accompany the invariant. Can provide a string, or a function that returns a string for cases where the message takes a fair amount of effort to compute.
+ *  
+ * @returns {asserts condition is true}
+ * @example
+ * ```tsx
+ * import invariant from 'tiny-invariant';
+ *
+ * // throws when 1 no longer equals 1
+ * invariant(1 === 1, 'Maths is broken');
+ * ```
+ */
 export default function invariant(condition: mixed, message?: string | (() => string)) {
   if (condition) {
     return;
diff --git a/src/tiny-invariant.ts b/src/tiny-invariant.ts
index 6c82392..6c42275 100644
--- a/src/tiny-invariant.ts
+++ b/src/tiny-invariant.ts
@@ -1,13 +1,25 @@
 const isProduction: boolean = process.env.NODE_ENV === 'production';
 const prefix: string = 'Invariant failed';
 
-// Throw an error if the condition fails
-// Strip out error messages for production
-// > Not providing an inline default argument for message as the result is smaller
+/**
+ * __invariant__
+ * 
+ * The `invariant` function takes a value, and if the value is falsy then the `invariant` function will throw. If the value is truthy, then the function will not throw.
+ *
+ * @param {*} condition A boolean condition - if falsy will throw an error.
+ * @param {(string|() => string)} message The message provided to accompany the invariant. Can provide a string, or a function that returns a string for cases where the message takes a fair amount of effort to compute.
+ *  
+ * @returns {asserts condition is true} Asserts condition is truthy.
+ * @example
+ * ```tsx
+ * import invariant from 'tiny-invariant';
+ *
+ * // throws when 1 no longer equals 1
+ * invariant(1 === 1, 'Maths is broken');
+ * ```
+ */
 export default function invariant(
   condition: any,
-  // Can provide a string, or a function that returns a string for cases where
-  // the message takes a fair amount of effort to compute
   message?: string | (() => string),
 ): asserts condition {
   if (condition) {