Added basic schema to field-configuration

experiments/config.mjs

@@ -1,4 +1,4 @@
-import { Field_Configuration  } from '@efforting.tech/data/field-configuration';
+import { Schema, Field_Configuration  } from '@efforting.tech/data/field-configuration';
 
 
 function mandatory_anything(value) {
@@ -15,7 +15,8 @@ function string_coercion_function(value) {
 
 
 
-const fc = new Field_Configuration('Some_Field', null, string_coercion_function, 'Anything that could be a string');
+const fc = new Field_Configuration(null, string_coercion_function, null, 'Anything that could be a string');
+const fd = new Field_Configuration(null, string_coercion_function, () => 'baz', 'A string. Defaults to \'baz\'');
 
 console.log(fc.check_validation(undefined));
 console.log(fc.check_validation(true));
@@ -23,9 +24,27 @@ console.log(fc.check_validation(true));
 console.log([ fc.coerce(123) ]);
 console.log([ fc.coerce(true) ]);
 
-console.log([ fc.load(undefined, 'Some configuration') ]);
+// console.log([ fc.load(undefined, 'Some configuration') ]);
-console.log([ fc.load(true) ]);
+// console.log([ fc.load(true) ]);
 
 
 //fc.validate(undefined);
-console.log(fc.load(undefined, 'New thingamabob object'));
+//console.log(fc.load(undefined, 'New thingamabob object'));
+
+
+const s = new Schema({
+	foo: fc,
+	bar: fd,
+});
+
+const s2 = new Schema({
+	thing: fc,
+	stuff: s,
+});
+
+console.log(s2.load({
+	stuff: { foo: 'Hello World' },
+	thing: 123,
+}));
+
+// { thing: '123', stuff: { foo: 'Hello World', bar: 'baz' } }

source/data/field-configuration.mjs

@@ -1,8 +1,8 @@
-import { Data_Validation_Failed, Data_Coercion_Failed } from '@efforting.tech/errors';
+import { Data_Validation_Failed, Data_Coercion_Failed, Superfluous_Data_Field } from '@efforting.tech/errors';
 
 export class Field_Configuration {
-	constructor(name, validation_function=null, coercion_function=null, expected_description=undefined) {
+	constructor(validation_function=null, coercion_function=null, factory_function=null, expected_description=undefined) {
-		Object.assign(this, { name, validation_function, coercion_function, expected_description });
+		Object.assign(this, { validation_function, coercion_function, factory_function, expected_description });
 	}
 
 	check_validation(value) {
@@ -11,29 +11,36 @@ export class Field_Configuration {
 	}
 
 	validate(value, target=undefined) {
-		const { validation_function, name, expected_description } = this;
+		const { validation_function, expected_description } = this;
 		if (!this.check_validation(value)) {
 			throw new Data_Validation_Failed({
-				name, validation_function, value,
+				validation_function, value,
 				target, expected_description,
 			});
 		}
 	}
 
 	coerce(value, target=undefined) {
-		const { coercion_function, name, expected_description } = this;
+		const { coercion_function, expected_description } = this;
 		try {
 			return coercion_function ? coercion_function(value) : value;
 		} catch (e) {
 			throw new Data_Coercion_Failed({
-				name, coercion_function, value,
+				coercion_function, value,
 				target, expected_description,
 				upstream_error: e,
 			})
 		}
 	}
 
-	load(value, target=undefined) {
+	load(value=undefined, target=undefined) {
+
+		const { factory_function } = this;
+
+		if ((value === undefined) && factory_function) {
+			value = factory_function(target);
+		}
+
 		const coerced_value = this.coerce(value, target);
 		this.validate(coerced_value, target);
 		return coerced_value;
@@ -41,3 +48,32 @@ export class Field_Configuration {
 
 
 }
+
+
+export class Schema {
+
+	constructor(field_schema) {
+		Object.assign(this, { field_schema });
+	}
+
+	load(value={}, target=undefined) {
+		const { field_schema } = this;
+
+		for (const [value_name, value_value] of Object.entries(value)) {
+			if (!field_schema[value_name]) {
+				throw new Superfluous_Data_Field({
+					field_value: value_value, field_name: value_name, target,
+				});
+			}
+		}
+
+		const result = {};
+		for (const [field_name, field_config] of Object.entries(field_schema)) {
+			const sub_target = { schema: this, field_name, field_config, parent_target: target };
+			result[field_name] = field_config.load(value[field_name], sub_target);
+		}
+
+		return result;
+	}
+
+}

source/errors.mjs

@@ -4,24 +4,43 @@ import { inspect } from 'node:util';
 
 export class Data_Validation_Failed extends Error {
 	constructor(data) {
-		const { value, target, expected_description, validation_function, name, upstream_error } = data;
+		const { value, target, expected_description, validation_function, upstream_error } = data;
 		const type = value === null ? 'null' : typeof value;
-		const target_info = target ? inspect(target) : 'unknown target';
+
+		const target_info = target?.info ? inspect(target.info) : 'unknown target';
+		const field_ref = target?.name ? `field "${target.name}"` : 'unknown field';
+
 		const expected_desc = expected_description ?? `data that would pass validation using ${validation_function}`;
 		const upstream_error_description = upstream_error ? ` Upstream error was: ${upstream_error}` : '';
-		super(`Data validation failed for field "${name}" of ${target_info}. Encountered data of type "${type}" while expecting "${expected_desc}".${upstream_error_description}`);
+		super(`Data validation failed for ${field_ref} of ${target_info}. Encountered data of type "${type}" while expecting "${expected_desc}".${upstream_error_description}`);
+		this.data = data;
+	}
+}
+
+export class Superfluous_Data_Field extends Error {
+	constructor(data) {
+		const { field_value, field_name, target, upstream_error } = data;
+		const type = field_value === null ? 'null' : typeof field_value;
+
+		const target_info = target?.info ? inspect(target.info) : 'unknown target';
+
+		const upstream_error_description = upstream_error ? ` Upstream error was: ${upstream_error}` : '';
+		super(`Data validation failed for ${target_info}. Superfluous field "${field_name}" with value of type "${type}" encountered.${upstream_error_description}`);
 		this.data = data;
 	}
 }
 
 export class Data_Coercion_Failed extends Error {
 	constructor(data) {
-		const { value, target, expected_description, coercion_function, name, upstream_error } = data;
+		const { value, target, expected_description, coercion_function, upstream_error } = data;
 		const type = value === null ? 'null' : typeof value;
-		const target_info = target ? inspect(target) : 'unknown target';
+
+		const target_info = target?.info ? inspect(target.info) : 'unknown target';
+		const field_ref = target?.name ? `field "${target.name}"` : 'unknown field';
+
 		const expected_desc = expected_description ?? `data that would be coerced using ${coercion_function}`;
 		const upstream_error_description = upstream_error ? ` Upstream error was: ${upstream_error}` : '';
-		super(`Data coercion failed for field "${name}" of ${target_info}. Encountered data of type "${type}" while expecting "${expected_desc}".${upstream_error_description}`);
+		super(`Data coercion failed for ${field_ref} of ${target_info}. Encountered data of type "${type}" while expecting "${expected_desc}".${upstream_error_description}`);
 		this.data = data;
 	}
 }