TokenValue.ts

/*
 * Copyright (c) 2020, J2 Innovations. All Rights Reserved
 */

import { HVal } from '../core/HVal'
import { HBool } from '../core/HBool'
import { TokenType } from './TokenType'
import { Token } from './Token'
import { HaysonVal } from '../core/hayson'

/**
 * A token that has a decoded haystack value.
 */
export class TokenValue implements Token {
	/**
	 * The token type.
	 */
	public readonly type: TokenType

	/**
	 * The haystack value.
	 */
	public readonly value: HVal

	/**
	 * Flag used to identify a token value.
	 */
	public readonly _isATokenValue = true

	/**
	 * Contructs a new token value.
	 *
	 * @param type The token type.
	 * @param text The token's text.
	 * @param value The tokens value.
	 */
	public constructor(type: TokenType, value: HVal) {
		this.type = type
		this.value = value
	}

	/**
	 * Return a boolean token value.
	 *
	 * @param value The boolean value.
	 * @returns The token value.
	 */
	public static makeBool(value: boolean): TokenValue {
		return new TokenValue(TokenType.boolean, HBool.make(value))
	}

	/**
	 * Returns true if the type matches this token's type.
	 *
	 * @param type The token type.
	 * @return True if the type matches.
	 */
	public is(type: TokenType): boolean {
		return this.type === type
	}

	/**
	 * Returns true if the object matches this one.
	 *
	 * @param type The token type.
	 * @param text The text.
	 * @return True if the objects are equal.
	 */
	public equals(token: Token): boolean {
		if (!isTokenValue(token)) {
			return false
		}

		return this.type === token.type && this.value.equals(token.value)
	}

	/**
	 * @returns A string representation of the token.
	 */
	public toString(): string {
		return this.value.toString()
	}

	/**
	 * @returns The encoded value that can be used in a haystack filter.
	 */
	public toFilter(): string {
		return this.value.toFilter()
	}

	/**
	 * @returns A JSON representation of the token.
	 */
	public toJSON(): {
		type: string
		[prop: string]: string | string[] | HaysonVal
	} {
		return {
			type: TokenType[this.type],
			val: this.value.toJSON(),
		}
	}
}

/**
 * Test to see if the value is an instance of a token value.
 */
export function isTokenValue(value: unknown): value is TokenValue {
	return !!(value && (value as TokenValue)._isATokenValue)
}