Schema compilation

JSON schemas are compiled by the compiler. This converts the schema into a simple JavaScript validation function that validates the data much faster than validating against the schema. The compiled schemas are not stored in any way and for each request, the schema must be compiled before the validation process. Since the actual step of compiling schemas is quite time consuming, the library supports creating a custom cache for compiled JSON schemas, thus eliminating this drawback. The @ptsq/cached-json-schema-parser (opens in a new tab) module allows you to create an in-memory cache for compiled validation functions. It uses lazy compilation, i.e. the schema is compiled the first time the validation is run over a given JSON schema, after that the compilation is never run again and the stored value of the validation function is used.

The schema validator or parser can be set up when creating a PTSQ instance and can be modified to use libraries other than Typebox to compile JSON schemas, such as the popular AJV compiler. Typebox schemas are compatible with any tool supporting the JSON Schema Draft 7 specification.

Custom parser with cache using Typebox

import { TSchema } from '@ptsq/server';
import { TypeCheck, TypeCompiler } from '@sinclair/typebox/compiler';
 
const cache = new Map<TSchema, TypeCheck<TSchema>>();
 
ptsq({
  parser: {
    encode: ({ value, schema }) => {
      let compiledSchema = cache.get(schema);
 
      if (!compiledSchema) {
        compiledSchema = TypeCompiler.Compile(schema);
        cache.set(schema, compiledSchema);
      }
 
      try {
        return {
          ok: true,
          data: compiledSchema.Encode(value),
        };
      } catch (error) {
        return {
          ok: false,
          errors: [...compiledSchema.Errors(value)],
        };
      }
    },
    decode: ({ value, schema }) => {
      let compiledSchema = cache.get(schema);
 
      if (!compiledSchema) {
        compiledSchema = TypeCompiler.Compile(schema);
        cache.set(schema, compiledSchema);
      }
 
      try {
        return {
          ok: true,
          data: compiledSchema.Decode(value),
        };
      } catch (error) {
        return {
          ok: false,
          errors: [...compiledSchema.Errors(value)],
        };
      }
    },
  },
});

Schema transformation Description