feat: Add ConfigField class

src/config-field.js

@@ -0,0 +1,161 @@
+import { ConfigFieldBaseType as BaseType } from './types';
+
+/**
+ * @public
+ * @class
+ */
+class ConfigField {
+ /**
+ * @param {object} config
+ * @param {string} config.name - name of this field
+ * @param {string} config.comment - comment for this field
+ * @param {string} config.sample - sample of value
+ * @param {ConfigFieldBaseType} config.type - type of value
+ * @param {(boolean|function.<boolean>)=} config.required
+ * [if default is undefined, by default this field set to 'true']
+ * @param {functions[]} config.preTransforms
+ * [array of transformation for value, apply before validation]
+ * @param {{ pre: function[], post: function[] }} config.transforms [transforms for value]
+ * @param {functions[]} config.postTransforms
+ * [array of transformation for value, apply after validation]
+ * @param {functions.<boolean>[]} config.validators [array of validators for value]
+ * @param {*} config.default [default value for this field]
+ */
+ constructor(config) {
+ /**
+ * @type {string}
+ */
+ this.comment = config.comment || '';
+ /**
+ * @type {string}
+ */
+ this.sample = config.sample || config.default || '';
+
+ /**
+ * @type {*}
+ */
+ this.default = config.default;
+
+ // if 'default' value is undefined, by default this rule required flag set to true
+ /**
+ * @type {boolean}
+ */
+ this.required = ((this.default === null || this.default === undefined) &&
+ (config.required === null || config.required === undefined || config.required === true));
+
+ if (!(config.type instanceof BaseType)) {
+ throw new Error('Type of field must be object extend from base ConfigFieldType');
+ }
+ /**
+ * @type {ConfigFieldBaseType}
+ */
+ this.type = config.type;
+
+ /**
+ * @type {{ pre: function[], post: function[] }}
+ */
+ this.transformators = {
+ pre: [...this.type.transformators.pre],
+ post: [...this.type.transformators.post],
+ };
+
+ if (config.transforms) {
+ if (config.transforms.pre && config.transforms.pre instanceof Array) {
+ this.transformators.pre.push(...config.transforms.pre);
+ }
+ if (config.transforms.post && config.transforms.post instanceof Array) {
+ this.transformators.post.push(...config.transforms.post);
+ }
+ }
+
+ if (config.preTransforms && config.preTransforms instanceof Array) {
+ this.transformators.pre.push(...config.preTransforms);
+ }
+
+ if (config.postTransforms && config.postTransforms instanceof Array) {
+ this.transformators.pre.push(...config.postTransforms);
+ }
+
+ /**
+ * @type {function.<boolean>[]}
+ */
+ this.validators = [...this.type.validators, ...(config.validators || [])];
+ }
+
+ /**
+ * @method validate
+ * @param {*=} value
+ * @return {*}
+ */
+ validate(value) {
+ let newValue;
+
+ if ((value === undefined || value === null)) {
+ if (this.required) {
+ throw new Error('This field is required');
+ }
+
+ newValue = this.default;
+ }
+
+ if (!(value === undefined || value === null)) {
+ try {
+ newValue = this.applyPreTransforms(value);
+ } catch (err) {
+ const newError = new Error('Can\'t apply pre-transform to value');
+ newError.error = err;
+ throw newError;
+ }
+ }
+
+ try {
+ if (!this.applyValidators(newValue)) {
+ throw new Error();
+ }
+ } catch (err) {
+ const newError = new Error('Validation error');
+ newError.error = err;
+ throw newError;
+ }
+
+ try {
+ newValue = this.applyPostTransforms(newValue);
+ } catch (err) {
+ const newError = new Error('Can\'t apply post-transforms to value');
+ newError.error = err;
+ throw newError;
+ }
+
+ return newValue;
+ }
+
+ /**
+ * @method applyPreTransforms
+ * @param {*} value
+ * @return {*}
+ */
+ applyPreTransforms(value) {
+ return this.transformators.pre.reduce((val, fn) => fn(val), value);
+ }
+
+ /**
+ * @method applyValidators
+ * @param {*} value
+ * @return {boolean}
+ */
+ applyValidators(value) {
+ return this.validators.every(fn => fn(value));
+ }
+
+ /**
+ * @method applyPostTransforms
+ * @param {*} value
+ * @return {*}
+ */
+ applyPostTransforms(value) {
+ return this.transformators.post.reduce((val, fn) => fn(val), value);
+ }
+}
+
+export default ConfigField;
+module.exports = ConfigField;