pip-services3-commons-node/src/validate/ValueComparisonRule.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 { ObjectComparator } from './ObjectComparator';
import { ValidationResultType } from './ValidationResultType';

/**
 * Validation rule that compares value to a constant.
 * 
 * @see [[IValidationRule]]
 * 
 * ### Example ###
 * 
 *     let schema = new Schema()
 *         .withRule(new ValueComparisonRule("EQ", 1));
 *     
 *     schema.validate(1);          // Result: no errors
 *     schema.validate(2);          // Result: 2 is not equal to 1
 */
export class ValueComparisonRule implements IValidationRule {
    private readonly _value: any;
    private readonly _operation: string;

    /**
     * Creates a new validation rule and sets its values.
     * 
     * @param operation    a comparison operation: "==" ("=", "EQ"), "!= " ("<>", "NE"); "<"/">" ("LT"/"GT"), "<="/">=" ("LE"/"GE"); "LIKE".
     * @param value        a constant value to compare to
     */
    public constructor(operation: string, value: any) {
        this._operation = operation;
        this._value = value;
    }

    /**
     * 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 {
        let name = path || "value";

        if (!ObjectComparator.compare(value, this._operation, this._value)) {
            results.push(
                new ValidationResult(
                    path,
                    ValidationResultType.Error,
                    "BAD_VALUE",
                    name + " must " + this._operation + " " + this._value + " but found " + value,
                    this._operation + " " + this._value,
                    value
                )
            );
        }
    }

}