Standard libraries that lift up your code.
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import {Valid, ValidationResult, ValidationRules, ValidatorFunction, ValidatorFunctionParams} from './rules/types'
import {Messages, ErrorWithContext, dataWalkUnsafe, dataSetUnsafe} from '../util'
/**
* An error thrown thrown when an object fails its validation.
*/
export class ValidationError<T> extends ErrorWithContext {
constructor(
/** The original input data. */
public readonly data: unknown,
/** The validator instance used. */
public readonly validator: Validator<T>,
/** Validation error messages, by field. */
public readonly errors: Messages,
) {
super('One or more fields were invalid.', { data,
messages: errors.all() })
}
}
/**
* A class to validate arbitrary data using functional rules.
*/
export class Validator<T> {
constructor(
/** The rules used to validate input objects. */
protected readonly rules: ValidationRules,
) {}
/**
* Attempt to validate the input data.
* If it is valid, it is type aliased as Valid<T>.
* If it is invalid, a ValidationError is thrown.
* @param data
*/
public async validate(data: unknown): Promise<Valid<T>> {
const messages = await this.validateAndGetErrors(data)
if ( messages.any() ) {
throw new ValidationError<T>(data, this, messages)
}
return data as Valid<T>
}
/**
* Returns true if the given data is valid and type aliases it as Valid<T>.
* @param data
*/
public async isValid(data: unknown): Promise<boolean> {
return !(await this.validateAndGetErrors(data)).any()
}
/**
* Apply the validation rules to the data object and return any error messages.
* @param data
* @protected
*/
protected async validateAndGetErrors(data: unknown): Promise<Messages> {
const messages = new Messages()
const params: ValidatorFunctionParams = { data }
for ( const key in this.rules ) {
if ( !Object.prototype.hasOwnProperty.call(this.rules, key) ) {
continue
}
// This walks over all of the values in the data structure using the nested
// key notation. It's not type-safe, but neither is the original input object
// yet, so it's useful here.
for ( const walkEntry of dataWalkUnsafe<any>(data as any, key) ) {
let [entry, dataKey] = walkEntry // eslint-disable-line prefer-const
const rules = (Array.isArray(this.rules[key]) ? this.rules[key] : [this.rules[key]]) as ValidatorFunction[]
for ( const rule of rules ) {
const result: ValidationResult = await rule(dataKey, entry, params)
if ( !result.valid ) {
let errors = ['is invalid']
if ( Array.isArray(result.message) && result.message.length ) {
errors = result.message
} else if ( !Array.isArray(result.message) && result.message ) {
errors = [result.message]
}
for ( const error of errors ) {
if ( !messages.has(dataKey, error) ) {
messages.put(dataKey, error)
}
}
}
if ( result.valid && result.castValue ) {
entry = result.castValue
data = dataSetUnsafe(dataKey, entry, data as any)
}
if ( result.stopValidation ) {
break // move on to the next field
}
}
}
}
return messages
}
}