Mimlet
@mimletdev.bsky.social
TypeScript test-data toolkit. Build from schemas or factories, connect fixtures explicitly, and replay property failures with fast-check. Alpha.
https://jeffreynijs.github.io/mimlet/
https://jeffreynijs.github.io/mimlet/
Pinned
A checkout fixture changes customer, but its order still points at the old ID.
Mimlet makes those dependencies explicit, so new builds stay coherent. Start from schemas or factories; explore and replay cases with fast-check.
Alpha 0.1.0-alpha.2
jeffreynijs.github.io/mimlet/
Mimlet makes those dependencies explicit, so new builds stay coherent. Start from schemas or factories; explore and replay cases with fast-check.
Alpha 0.1.0-alpha.2
jeffreynijs.github.io/mimlet/
Mimlet's first beta is out: 0.1.0-beta.0, and a plain npm install gets it.
New: long enum values and UTC date-times generate as they should, and every error code is documented.
Try it, tell us what's confusing:
npm i -D @mimlet/zod zod
jeffreynijs.github.io/mimlet/guide/beta-feedback
#TypeScript
New: long enum values and UTC date-times generate as they should, and every error code is documented.
Try it, tell us what's confusing:
npm i -D @mimlet/zod zod
jeffreynijs.github.io/mimlet/guide/beta-feedback
#TypeScript
October 3, 2026 at 12:42 PM
Mimlet's first beta is out: 0.1.0-beta.0, and a plain npm install gets it.
New: long enum values and UTC date-times generate as they should, and every error code is documented.
Try it, tell us what's confusing:
npm i -D @mimlet/zod zod
jeffreynijs.github.io/mimlet/guide/beta-feedback
#TypeScript
New: long enum values and UTC date-times generate as they should, and every error code is documented.
Try it, tell us what's confusing:
npm i -D @mimlet/zod zod
jeffreynijs.github.io/mimlet/guide/beta-feedback
#TypeScript
npm only warns about an unsupported peer. Then your test fails deep inside effect.
npx mimlet doctor names the cause: @mimlet/effect supports effect 3.22.2, but 4.0.0 is installed. --json gives agents stable codes.
npm i -D @mimlet/codegen
jeffreynijs.github.io/mimlet/guide/cli-diagnostics
npx mimlet doctor names the cause: @mimlet/effect supports effect 3.22.2, but 4.0.0 is installed. --json gives agents stable codes.
npm i -D @mimlet/codegen
jeffreynijs.github.io/mimlet/guide/cli-diagnostics
October 2, 2026 at 5:37 PM
npm only warns about an unsupported peer. Then your test fails deep inside effect.
npx mimlet doctor names the cause: @mimlet/effect supports effect 3.22.2, but 4.0.0 is installed. --json gives agents stable codes.
npm i -D @mimlet/codegen
jeffreynijs.github.io/mimlet/guide/cli-diagnostics
npx mimlet doctor names the cause: @mimlet/effect supports effect 3.22.2, but 4.0.0 is installed. --json gives agents stable codes.
npm i -D @mimlet/codegen
jeffreynijs.github.io/mimlet/guide/cli-diagnostics
ArkType rules in, valid fixtures out.
fromArkType(User) samples values that satisfy every rule, like 'string.email'.
Break one and you get ArkType's own message: age must be at least 18 (was 15).
npm i -D @mimlet/arktype [email protected]
jeffreynijs.github.io/mimlet/guide/zod-and-arktype
fromArkType(User) samples values that satisfy every rule, like 'string.email'.
Break one and you get ArkType's own message: age must be at least 18 (was 15).
npm i -D @mimlet/arktype [email protected]
jeffreynijs.github.io/mimlet/guide/zod-and-arktype
October 2, 2026 at 3:30 PM
ArkType rules in, valid fixtures out.
fromArkType(User) samples values that satisfy every rule, like 'string.email'.
Break one and you get ArkType's own message: age must be at least 18 (was 15).
npm i -D @mimlet/arktype [email protected]
jeffreynijs.github.io/mimlet/guide/zod-and-arktype
fromArkType(User) samples values that satisfy every rule, like 'string.email'.
Break one and you get ArkType's own message: age must be at least 18 (was 15).
npm i -D @mimlet/arktype [email protected]
jeffreynijs.github.io/mimlet/guide/zod-and-arktype
New in alpha.2: named setters, no builder file.
const users = fluent(fromZod(User), ['name'])
users.withName('Ada').build()
Pick the fields you want. The setters use your schema's input types.
npm i -D @mimlet/core @mimlet/zod
jeffreynijs.github.io/mimlet/guide/fluent-builders
const users = fluent(fromZod(User), ['name'])
users.withName('Ada').build()
Pick the fields you want. The setters use your schema's input types.
npm i -D @mimlet/core @mimlet/zod
jeffreynijs.github.io/mimlet/guide/fluent-builders
October 2, 2026 at 11:34 AM
New in alpha.2: named setters, no builder file.
const users = fluent(fromZod(User), ['name'])
users.withName('Ada').build()
Pick the fields you want. The setters use your schema's input types.
npm i -D @mimlet/core @mimlet/zod
jeffreynijs.github.io/mimlet/guide/fluent-builders
const users = fluent(fromZod(User), ['name'])
users.withName('Ada').build()
Pick the fields you want. The setters use your schema's input types.
npm i -D @mimlet/core @mimlet/zod
jeffreynijs.github.io/mimlet/guide/fluent-builders
October 1, 2026 at 1:55 PM
1/3 With TypeBox, a delivery-to-pickup switch needs the whole union branch. Mimlet’s fromTypeBoxVariant() selects that shape, including pickupCode, and native validation checks the result.
Mimlet alpha
jeffreynijs.github.io/mimlet/
Mimlet alpha
jeffreynijs.github.io/mimlet/
October 1, 2026 at 1:41 PM
1/3 With TypeBox, a delivery-to-pickup switch needs the whole union branch. Mimlet’s fromTypeBoxVariant() selects that shape, including pickupCode, and native validation checks the result.
Mimlet alpha
jeffreynijs.github.io/mimlet/
Mimlet alpha
jeffreynijs.github.io/mimlet/
A checkout fixture changes customer, but its order still points at the old ID.
Mimlet makes those dependencies explicit, so new builds stay coherent. Start from schemas or factories; explore and replay cases with fast-check.
Alpha 0.1.0-alpha.2
jeffreynijs.github.io/mimlet/
Mimlet makes those dependencies explicit, so new builds stay coherent. Start from schemas or factories; explore and replay cases with fast-check.
Alpha 0.1.0-alpha.2
jeffreynijs.github.io/mimlet/
October 1, 2026 at 12:59 PM
A checkout fixture changes customer, but its order still points at the old ID.
Mimlet makes those dependencies explicit, so new builds stay coherent. Start from schemas or factories; explore and replay cases with fast-check.
Alpha 0.1.0-alpha.2
jeffreynijs.github.io/mimlet/
Mimlet makes those dependencies explicit, so new builds stay coherent. Start from schemas or factories; explore and replay cases with fast-check.
Alpha 0.1.0-alpha.2
jeffreynijs.github.io/mimlet/