Docs

faker

Struct Data Fake Generator

Faker will generate you a fake data based on your Struct.

Index

• Support
• Getting Started
• Example
• Limitation
• Contribution

Support

You can file an Issue. See documentation in Go.Dev

Getting Started

Download

go get -u github.com/go-faker/faker/v4

Example

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• Using Struct's tag:
  • basic tags: example_with_tags_test.go
  • length and bounds: example_with_tags_lenbounds_test.go
  • language: example_with_tags_lang_test.go
  • unique: example_with_tags_unique_test.go
  • slice length: example_with_tags_slicelength_test.go
  • template (derived fields): example_template_tag_test.go
• Custom Struct's tag (define your own faker data): example_custom_faker_test.go
• Without struct's tag: example_without_tag_test.go
• Single Fake Data Function: example_single_fake_data_test.go
• custom struct type providers : example_custom_struct_test.go
• large nested (& circular) struct with map & slice size limits & depth limitations : example_with_limits_test.go

DEMO

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Benchmark

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Bench To Generate Fake Data

Without Tag

BenchmarkFakerDataNOTTagged-4             500000              3049 ns/op             488 B/op         20 allocs/op

Using Tag

 BenchmarkFakerDataTagged-4                100000             17470 ns/op             380 B/op         26 allocs/op

MUST KNOW

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The Struct Field must be PUBLIC.
Support For :

• pointer fields of any type
• int, int8, int16, int32 & int64
• uint, uint8, uint16, uint32 & uint64
• bool
• string
• float32, float64
• struct & nested struct
• slice / array of any type
• map of any key/value of supported types
• custom struct types by registering a StructTypeProvider & implementing your own generator function. This can be used for redefined time, big.Rat, etc. See example for usage.
  • default time.Time provider is registered, you can override it by registering your own provider.

Limitation

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Unfortunately this library has some limitation

• It does not support private fields. Make sure your structs fields you intend to generate fake data for are public, it would otherwise trigger a panic. You can however omit fields using a tag skip faker:"-" on your private fields.
• It does not support the any (empty interface) data type. How could we generate anything without knowing its data type?
• It does not support the map[any]any, map[T]any & map[any]T data types (where T is any concrete type). Once again, we cannot generate values for an unknown data type.
• Some extra custom types can be supported IF AND ONLY IF extended with AddProvider() please see example
• The oneof tag currently only supports string, the int types, and both float32 & float64. Further support is coming soon (i.e. hex numbers, etc). See example for usage.
• The template tag currently only supports string, named string types & *string, and can only reference the fields of the struct that declares it. See example for usage.

Contribution

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To contrib to this project, you can open a PR or an issue.