pip-services3-commons-node/src/validate/NotRule.ts

Portable abstractions and patterns for Pip.Services in Node.js

/** @module validate */
import { IValidationRule } from './IValidationRule';
import { Schema } from './Schema';
import { ValidationResult } from './ValidationResult';
import { ValidationResultType } from './ValidationResultType';

/**
 * Validation rule negate another rule.
 * When embedded rule returns no errors, than this rule return an error.
 * When embedded rule return errors, than the rule returns no errors.
 * 
 * @see [[IValidationRule]]
 * 
 * ### Example ###
 * 
 *     let schema = new Schema()
 *         .withRule(new NotRule(
 *             new ValueComparisonRule("EQ", 1)
 *         ));
 *     
 *     schema.validate(1);          // Result: error
 *     schema.validate(5);          // Result: no error
 */
export class NotRule implements IValidationRule {
    private readonly _rule: IValidationRule;

    /**
     * Creates a new validation rule and sets its values
     * 
     * @param rule     a rule to be negated.
     */
    public constructor(rule: IValidationRule) {
        this._rule = rule;
    }

    /**
     * Validates a given value against this rule.
     * 
     * @param path      a dot notation path to the value.
     * @param schema    a schema this rule is called from
     * @param value     a value to be validated.
     * @param results   a list with validation results to add new results.
     */
    public validate(path: string, schema: Schema, value: any, results: ValidationResult[]): void {
        if (!this._rule) return;

        let name = path || "value";
        let localResults: ValidationResult[] = [];

        this._rule.validate(path, schema, value, localResults);

        if (localResults.length > 0) return;

        results.push(
            new ValidationResult(
                path,
                ValidationResultType.Error,
                "NOT_FAILED",
                "Negative check for " + name + " failed",
                null,
                null
            )
        );
    }

}