typescript-best-practices

Provides TypeScript patterns for type-first development, making illegal states unrepresentable, exhaustive handling, and runtime validation. Must use when reading or writing TypeScript/JavaScript files.

1.11x

Quality

77%

Does it follow best practices?

Impact

96%

1.11x

Average score across 3 eval scenarios

Securityby

Passed

No known issues

Optimize this skill with Tessl

npx tessl skill review --optimize ./data/skills-md/0xbigboss/claude-code/typescript-best-practices/SKILL.md

Evaluation results

96%

17%

Payment Order Lifecycle Tracker

Discriminated unions and exhaustive handling

Criteria

Without context

With context

Discriminated union states

100%

State-specific fields

100%

Branded order ID type

100%

Branded customer ID type

100%

Const assertion literal union

100%

Exhaustive switch with never

66%

Error messages include context

100%

No parameter mutation

100%

Array methods over for loops

100%

Pure business logic

87%

100%

Const over let

100%

Test edge cases

100%

Without context: $0.6062 · 2m 25s · 27 turns · 33 in / 9,812 out tokens

With context: $0.6252 · 2m 4s · 30 turns · 34 in / 8,072 out tokens

100%

User Profile API Input Validation

Zod runtime validation and schema composition

Criteria

Without context

With context

Zod schema as source of truth

100%

safeParse for user input

100%

parse at trust boundary

100%

Schema composition - not duplication

70%

100%

Transform for normalization

100%

Custom refine with descriptive error

100%

Return result to caller

100%

Descriptive field error messages

100%

Partial update schema

100%

Date transform

100%

Test covers both parse paths

100%

Without context: $0.5565 · 2m 28s · 27 turns · 33 in / 9,015 out tokens

With context: $0.6551 · 2m 35s · 29 turns · 316 in / 9,134 out tokens

94%

12%

Microservice Configuration Bootstrap

Typed config from environment variables

Criteria

Without context

With context

Zod schema for config

100%

Config type from schema

20%

50%

Parsed at module load

83%

100%

Invalid config crashes

60%

100%

Defaults for non-secrets

100%

No defaults for secrets

100%

No process.env in other code

75%

100%

Coerced numeric port

87%

100%

Enum for log level

100%

Boolean feature flag

85%

Test: missing required field throws

100%

Without context: $0.4877 · 1m 55s · 24 turns · 29 in / 7,499 out tokens

With context: $0.7054 · 2m 29s · 33 turns · 37 in / 9,090 out tokens

Repository: NeverSight/skills_feed
Commit: 5342bca

Evaluated: 13 days ago
Agent: Claude Code
Model: Claude Sonnet 4.6

Table of Contents

Payment Order Lifecycle Tracker User Profile API Input Validation Microservice Configuration Bootstrap

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