@sap/odata-v4/lib/format/AcceptTypeInfo.js

OData V4.0 server library

'use strict';

const ContentTypeInfo = require('./ContentTypeInfo');

/**
 * Used to store the parts of an accept type.
 *
 * @extends ContentTypeInfo
 * @hideconstructor
 */
class AcceptTypeInfo extends ContentTypeInfo {

    /**
     * Constructor
     * @param {string} typeAndSubtype Mime type and subtype
     */
    constructor(typeAndSubtype) {
        super();
        super.setMimeType(typeAndSubtype);

        /**
         * @type {number}
         * @private
         */
        this._quality = 1;
    }

    /**
     * Set the quality.
     * @param {number} quality
     * @returns {AcceptTypeInfo}
     * @package
     */
    setQuality(quality) {
        this._quality = quality;
        return this;
    }

    /**
     * Return the quality.
     * @returns {number} quality
     */
    getQuality() {
        return this._quality;
    }

    toString() {
        return super.toString() + (this._quality < 1 ? ';q=' + this._quality : '');
    }

    /**
     * Return true if the given MIME type is matched by this instance's MIME type
     * (which can contain '*'), false otherwise.
     * @param {string} mimeType
     * @returns {boolean}
     */
    match(mimeType) {
        const m = this.getMimeType();
        if (m.startsWith('*')) return true;
        if (m.endsWith('*')) return m.substring(0, m.indexOf('/')) === mimeType.substring(0, mimeType.indexOf('/'));
        return m === mimeType;
    }

    /**
     * Return a number indicating how two AcceptTypeInfo instances compare to each other
     * according to the sort order determined by quality-parameter value and specificity
     * (defined in RFC 7231, chapters 3.1.1.1, 5.3.1, and 5.3.2) as:
     * a negative value if a comes before b;
     * a positive value if a comes after b;
     * 0 if they are considered equal.
     * @param {AcceptTypeInfo} a
     * @param {AcceptTypeInfo} b
     * @returns {number} the comparison result (-1, 0, or 1)
     */
    static compare(a, b) {
        if (a.getQuality() !== b.getQuality()) return b.getQuality() - a.getQuality();
        // '^' is XOR in JavaScript.
        if (a.getMimeType().startsWith('*') ^ b.getMimeType().startsWith('*')) {
            return a.getMimeType().startsWith('*') ? 1 : -1;
        }
        if (a.getMimeType().endsWith('*') ^ b.getMimeType().endsWith('*')) {
            return a.getMimeType().endsWith('*') ? 1 : -1;
        }
        return b.getParameters().length - a.getParameters().length;
    }
}

module.exports = AcceptTypeInfo;