refactor: rewrite slow typings

- Remove redundant type recursions - Improve typing readability - Avoid casting Part of #2
profusion · May 25, 2023 · fb0f884 · fb0f884
1 parent f1c68ff
commit fb0f884
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Showing 13 changed files with 464 additions and 363 deletions.
diff --git a/examples/usage.ts b/examples/usage.ts
@@ -97,7 +97,7 @@ try {
   console.error('Failed to validate process.env variables:', error);
 
   if (error instanceof EnvSchemaValidationError) {
-    const e: EnvSchemaValidationError<typeof appVars, typeof customize> = error;
+    const e: EnvSchemaValidationError<typeof appVars> = error;
     // if you want to proceed anyway, the partial result is stored at:
     console.log('partial result:', e.values);
     console.log('errors:', JSON.stringify(e.errors, undefined, 2));

diff --git a/lib/convert.test.ts b/lib/convert.test.ts
@@ -4,13 +4,10 @@ process.env.VALIDATED_ENV_SCHEMA_DEBUG = 'true';
 import {
   commonSchemas,
   JSONSchema7,
+  TypeFromJSONSchema,
 } from '@profusion/json-schema-to-typescript-definitions';
 
-import {
-  EnvSchemaMaybeErrors,
-  EnvSchemaPartialValues,
-  schemaProperties,
-} from './types';
+import { EnvSchemaMaybeErrors, schemaProperties } from './types';
 import commonConvert from './common-convert';
 import createConvert from './convert';
 
@@ -34,17 +31,17 @@ describe('createConvert', (): void => {
     required: ['REQ_VAR'],
     type: 'object',
   } as const;
-  type S = typeof schema;
+  type V = TypeFromJSONSchema<typeof schema>;
 
   it('works without conversion', (): void => {
-    const values: EnvSchemaPartialValues<S> = {
+    const values = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
-    const container: Record<string, string | undefined> = {
+    } as const satisfies V;
+    const container = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
+    } as const satisfies V;
     const convert = createConvert(schema, schemaProperties(schema), undefined);
     const consoleSpy = getConsoleMock();
     const [convertedValue, conversionErrors] = convert(
@@ -66,22 +63,22 @@ describe('createConvert', (): void => {
   });
 
   it('works with valid schema', (): void => {
-    const values: EnvSchemaPartialValues<S> = {
+    const values = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
+    } as const satisfies V;
     const container = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    } as const;
+    } as const satisfies V;
     const convert = createConvert(schema, schemaProperties(schema), {
       OPT_VAR: (
         value: string | undefined,
         propertySchema: JSONSchema7,
         key: string,
         allSchema: JSONSchema7,
-        initialValues: EnvSchemaPartialValues<S>,
-        errors: EnvSchemaMaybeErrors<S>,
+        initialValues: Partial<V>,
+        errors: EnvSchemaMaybeErrors<typeof schema>,
       ): bigint | undefined =>
         typeof value === 'string' &&
         propertySchema === schema.properties.OPT_VAR &&
@@ -129,16 +126,16 @@ New Value.....: ${commonConvert.dateTime(container.REQ_VAR)}
   });
 
   it('works with missing values (keep undefined)', (): void => {
-    const values: EnvSchemaPartialValues<S> = {};
+    const values: Partial<V> = {};
     const container: Record<string, string | undefined> = {};
     const convert = createConvert(schema, schemaProperties(schema), {
       OPT_VAR: (
         value: string | undefined,
         propertySchema: JSONSchema7,
         key: string,
         allSchema: JSONSchema7,
-        initialValues: EnvSchemaPartialValues<S>,
-        errors: EnvSchemaMaybeErrors<S>,
+        initialValues: Partial<V>,
+        errors: EnvSchemaMaybeErrors<typeof schema>,
       ): bigint | undefined =>
         typeof value === 'string' &&
         propertySchema === schema.properties.OPT_VAR &&
@@ -167,16 +164,16 @@ New Value.....: ${commonConvert.dateTime(container.REQ_VAR)}
   });
 
   it('works with missing values (return custom default)', (): void => {
-    const values: EnvSchemaPartialValues<S> = {};
+    const values: Partial<V> = {};
     const container: Record<string, string | undefined> = {};
     const convert = createConvert(schema, schemaProperties(schema), {
       OPT_VAR: (
         value: string | undefined,
         propertySchema: JSONSchema7,
         key: string,
         allSchema: JSONSchema7,
-        initialValues: EnvSchemaPartialValues<S>,
-        errors: EnvSchemaMaybeErrors<S>,
+        initialValues: Partial<V>,
+        errors: EnvSchemaMaybeErrors<typeof schema>,
       ): bigint | undefined =>
         typeof value === 'string' &&
         propertySchema === schema.properties.OPT_VAR &&
@@ -222,14 +219,14 @@ New Value.....: ${new Date(0)}
   });
 
   it('removes properties converted to undefined', (): void => {
-    const values: EnvSchemaPartialValues<S> = {
+    const values = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
+    } as const satisfies V;
     const container: Record<string, string | undefined> = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
+    } as const satisfies V;
     const convert = createConvert(schema, schemaProperties(schema), {
       OPT_VAR: (): bigint | undefined => undefined,
       REQ_VAR: (): Date | undefined => undefined,
@@ -255,14 +252,14 @@ New Value.....: ${new Date(0)}
   });
 
   it('removes properties that conversion did throw', (): void => {
-    const values: EnvSchemaPartialValues<S> = {
+    const values = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
+    } as const satisfies V;
     const container: Record<string, string | undefined> = {
       OPT_VAR: '0x1fffffffffffff',
       REQ_VAR: '2021-01-02T12:34:56.000Z',
-    };
+    } as const satisfies V;
     const error = new Error('forced error');
     const convert = createConvert(schema, schemaProperties(schema), {
       OPT_VAR: (): bigint => {
@@ -303,7 +300,7 @@ New Value.....: ${new Date(0)}
       },
       type: 'object',
     } as const;
-    const values: EnvSchemaPartialValues<typeof schemaNoRequired> = {};
+    const values: TypeFromJSONSchema<typeof schemaNoRequired> = {};
     const container: Record<string, string | undefined> = {};
     const convert = createConvert(
       schemaNoRequired,

diff --git a/lib/convert.ts b/lib/convert.ts
@@ -1,12 +1,14 @@
+import type { TypeFromJSONSchema } from '@profusion/json-schema-to-typescript-definitions';
+
 import type {
+  BaseEnvParsed,
   BaseEnvSchema,
   EnvSchemaConvertedPartialValues,
   EnvSchemaConvertedPartialValuesWithConvert,
   EnvSchemaCustomConverters,
   EnvSchemaMaybeErrors,
   EnvSchemaProperties,
-  EnvSchemaPropertyValue,
-  EnvSchemaPartialValues,
+  KeyOf,
 } from './types';
 
 import { addErrors } from './errors';
@@ -15,50 +17,50 @@ import dbg from './dbg';
 // DO NOT THROW HERE!
 type EnvSchemaConvert<
   S extends BaseEnvSchema,
-  Converters extends EnvSchemaCustomConverters<S> | undefined,
+  V extends BaseEnvParsed<S> = TypeFromJSONSchema<S>,
+  Converters extends EnvSchemaCustomConverters<S, V> | undefined = undefined,
 > = (
-  value: EnvSchemaPartialValues<S>,
+  value: Partial<V>,
   errors: EnvSchemaMaybeErrors<S>,
   container: Record<string, string | undefined>,
 ) => [
-  EnvSchemaConvertedPartialValuesWithConvert<S, Converters>,
+  EnvSchemaConvertedPartialValuesWithConvert<S, Converters, V>,
   EnvSchemaMaybeErrors<S>,
 ];
 
 const noRequiredProperties: string[] = [];
 
 const createConvert = <
   S extends BaseEnvSchema,
-  Converters extends EnvSchemaCustomConverters<S>,
+  V extends BaseEnvParsed<S> = TypeFromJSONSchema<S>,
+  Converters extends EnvSchemaCustomConverters<
+    S,
+    V
+  > = EnvSchemaCustomConverters<S, V>,
 >(
   schema: S,
   properties: Readonly<EnvSchemaProperties<S>>,
   customize: Converters,
-): EnvSchemaConvert<S, Converters> => {
+): EnvSchemaConvert<S, V, Converters> => {
   const convertedProperties = properties.filter(
     ([key]) => customize[key] !== undefined,
   );
 
-  type ConverterKey = Extract<keyof Converters, string>;
-  const requiredProperties: readonly ConverterKey[] = schema.required
-    ? (schema.required.filter(
-        key => customize[key] !== undefined,
-      ) as ConverterKey[])
-    : (noRequiredProperties as ConverterKey[]);
+  type ConverterKey = KeyOf<Converters>;
+  const requiredProperties = schema.required
+    ? schema.required.filter(key => customize[key] !== undefined)
+    : noRequiredProperties;
 
   return (
-    initialValues: EnvSchemaPartialValues<S>,
+    initialValues: Partial<V>,
     initialErrors: EnvSchemaMaybeErrors<S>,
     container: Record<string, string | undefined>,
   ): [
-    EnvSchemaConvertedPartialValuesWithConvert<S, Converters>,
+    EnvSchemaConvertedPartialValuesWithConvert<S, Converters, V>,
     EnvSchemaMaybeErrors<S>,
   ] => {
     // alias the same object with a different type, save on casts
-    const values = initialValues as EnvSchemaConvertedPartialValuesWithConvert<
-      S,
-      Converters
-    >;
+    const values = initialValues;
     let errors = initialErrors;
 
     const removeValue = (key: ConverterKey): void => {
@@ -68,13 +70,14 @@ const createConvert = <
     };
 
     convertedProperties.forEach(([key, propertySchema]) => {
-      type K = typeof key;
       // it was filtered before
-      const convert = customize[key] as Exclude<Converters[K], undefined>;
+      const convert = customize[key] as NonNullable<
+        (typeof customize)[typeof key]
+      >;
       const oldValue = values[key];
       try {
         const newValue = convert(
-          values[key] as EnvSchemaPropertyValue<S, K> | undefined,
+          values[key],
           propertySchema,
           key,
           schema,
@@ -118,36 +121,39 @@ New Value.....: ${newValue}
       if (values[key] === undefined) {
         errors = addErrors(
           errors,
-          key as Extract<keyof S['properties'], string>,
+          key,
           new Error(`required property "${key}" is undefined`),
         );
       }
     });
 
-    return [values, errors];
+    return [
+      values as EnvSchemaConvertedPartialValuesWithConvert<S, Converters, V>,
+      errors,
+    ];
   };
 };
 
-const noConversion = <S extends BaseEnvSchema>(
-  values: EnvSchemaPartialValues<S>,
+const noConversion = <
+  S extends BaseEnvSchema,
+  V extends BaseEnvParsed<S> = TypeFromJSONSchema<S>,
+>(
+  values: Partial<V>,
   errors: EnvSchemaMaybeErrors<S>,
-): [EnvSchemaConvertedPartialValues<S, undefined>, EnvSchemaMaybeErrors<S>] => [
-  values as EnvSchemaConvertedPartialValues<S, undefined>,
+): [EnvSchemaConvertedPartialValues<S, never, V>, EnvSchemaMaybeErrors<S>] => [
+  values as EnvSchemaConvertedPartialValues<S, never, V>,
   errors,
 ];
 
 export default <
   S extends BaseEnvSchema,
-  Converters extends EnvSchemaCustomConverters<S> | undefined,
+  V extends BaseEnvParsed<S> = TypeFromJSONSchema<S>,
+  Converters extends EnvSchemaCustomConverters<S, V> | undefined = undefined,
 >(
   schema: Readonly<S>,
   properties: Readonly<EnvSchemaProperties<S>>,
   customize: Converters,
-): EnvSchemaConvert<S, Converters> =>
+): EnvSchemaConvert<S, V, Converters> =>
   customize === undefined
-    ? (noConversion as unknown as EnvSchemaConvert<S, Converters>)
-    : createConvert(
-        schema,
-        properties,
-        customize as Exclude<Converters, undefined>,
-      );
+    ? (noConversion as unknown as EnvSchemaConvert<S, V, Converters>)
+    : createConvert<S, V, typeof customize>(schema, properties, customize);
diff --git a/lib/errors.ts b/lib/errors.ts
@@ -1,9 +1,13 @@
+import type { TypeFromJSONSchema } from '@profusion/json-schema-to-typescript-definitions';
+
 import type {
   BaseEnvSchema,
   EnvSchemaConvertedPartialValues,
   EnvSchemaCustomizations,
   EnvSchemaMaybeErrors,
   EnvSchemaErrors,
+  BaseEnvParsed,
+  KeyOf,
 } from './types';
 
 /* istanbul ignore next */
@@ -13,14 +17,12 @@ export const assertIsError: (e: unknown) => asserts e is Error = e => {
 
 export const addErrors = <S extends BaseEnvSchema>(
   initialErrors: EnvSchemaMaybeErrors<S>,
-  key: Extract<keyof S['properties'], string> | '$other',
+  key: KeyOf<S['properties']> | '$other',
   exception: Error,
 ): EnvSchemaErrors<S> => {
-  let errors = initialErrors;
-  if (errors === undefined) errors = {};
-  let keyErrors = errors[key];
-  if (keyErrors === undefined) {
-    keyErrors = [];
+  const errors: EnvSchemaErrors<S> = initialErrors ?? {};
+  const keyErrors = errors[key] ?? [];
+  if (!keyErrors.length) {
     errors[key] = keyErrors;
   }
   keyErrors.push(exception);
@@ -40,11 +42,15 @@ export const addErrors = <S extends BaseEnvSchema>(
  */
 export class EnvSchemaValidationError<
   S extends BaseEnvSchema,
-  Customizations extends EnvSchemaCustomizations<S>,
+  V extends BaseEnvParsed<S> = TypeFromJSONSchema<S>,
+  Customizations extends EnvSchemaCustomizations<
+    S,
+    V
+  > = EnvSchemaCustomizations<S, V>,
 > extends Error {
   readonly schema: S;
 
-  values: EnvSchemaConvertedPartialValues<S, Customizations>;
+  values: EnvSchemaConvertedPartialValues<S, V, Customizations>;
 
   errors: EnvSchemaErrors<S>;
 
@@ -57,7 +63,7 @@ export class EnvSchemaValidationError<
     customize: Customizations,
     errors: EnvSchemaErrors<S>,
     container: Record<string, string | undefined>,
-    values: EnvSchemaConvertedPartialValues<S, Customizations>,
+    values: EnvSchemaConvertedPartialValues<S, V, Customizations>,
   ) {
     const names = Object.keys(errors).join(', ');
     super(`Failed to validate environment variables against schema: ${names}`);