enketo-core/src/js/preload.js

Extensible Enketo form engine

/**
 * Preloader module (soon to be deprecated).
 *
 * @module preloader
 */

import events from './event';

export default {
    /**
     * Initializes preloader
     */
    init() {
        if (!this.form) {
            throw new Error(
                'Preload module not correctly instantiated with form property.'
            );
        }

        // these initialize actual preload items
        this.form.view.html
            .querySelectorAll(
                'input[data-preload], select[data-preload], textarea[data-preload]'
            )
            .forEach((preloadEl) => {
                const props = this.form.input.getProps(preloadEl);
                const item =
                    preloadEl.dataset && preloadEl.dataset.preload
                        ? preloadEl.dataset.preload.toLowerCase()
                        : undefined;
                const param =
                    preloadEl.dataset && preloadEl.dataset.preloadParams
                        ? preloadEl.dataset.preloadParams.toLowerCase()
                        : undefined;

                if (typeof this[item] !== 'undefined') {
                    const dataNode = this.form.model.node(
                        props.path,
                        props.index
                    );
                    // If a preload item is placed inside a repeat with repeat-count 0, the node
                    // doesn't exist and will never get a value (which is correct behavior)
                    if (dataNode.getElements().length) {
                        const curVal = dataNode.getVal();
                        const newVal = this[item]({
                            param,
                            curVal,
                            dataNode,
                        });

                        dataNode.setVal(newVal, props.xmlType);
                    }
                } else {
                    console.warn(
                        `Preload "${item}" not supported. May or may not be a big deal.`
                    );
                }
            });
    },
    /**
     * @param {object} o - parameter object
     * @return {string} evaluated value or error message
     */
    timestamp(o) {
        let value;
        const that = this;
        // when is 'start' or 'end'
        if (o.param === 'start') {
            return o.curVal.length > 0
                ? o.curVal
                : this.form.model.evaluate('now()', 'string');
        }
        if (o.param === 'end') {
            // set event handler for each save event (needs to be triggered!)
            this.form.view.html.addEventListener(
                events.BeforeSave().type,
                () => {
                    value = that.form.model.evaluate('now()', 'string');
                    o.dataNode.setVal(value, 'datetime');
                }
            );

            // TODO: why populate this upon load?
            return this.form.model.evaluate('now()', 'string');
        }

        return 'error - unknown timestamp parameter';
    },
    /**
     * @param {object} o - parameter object
     * @return {string} current value or evaluated value
     */
    date(o) {
        let today;
        let year;
        let month;
        let day;

        if (o.curVal.length === 0) {
            today = new Date(this.form.model.evaluate('today()', 'string'));
            year = today.getFullYear().toString().padStart(4, '0');
            month = (today.getMonth() + 1).toString().padStart(2, '0');
            day = today.getDate().toString().padStart(2, '0');

            return `${year}-${month}-${day}`;
        }

        return o.curVal;
    },
    /**
     * @param {object} o - parameter object
     * @return {string} current value or evaluated value
     */
    property(o) {
        let node;

        // 'deviceid', 'subscriberid', 'simserial', 'phonenumber'
        if (o.curVal.length === 0) {
            node = this.form.model.node(
                `instance("__session")/session/context/${o.param}`
            );
            if (node.getElements().length) {
                return node.getVal();
            }
            return `no ${o.param} property in enketo`;
        }

        return o.curVal;
    },
    /**
     * @param {object} o - parameter object
     * @return {string} current value or evaluated value
     */
    context(o) {
        // 'application', 'user'??
        if (o.curVal.length === 0) {
            return o.param === 'application'
                ? 'enketo'
                : `${o.param} not supported in enketo`;
        }

        return o.curVal;
    },
    /**
     * @param {object} o - parameter object
     * @return {string} current value or error message
     */
    patient(o) {
        if (o.curVal.length === 0) {
            return 'patient preload item not supported in enketo';
        }

        return o.curVal;
    },
    /**
     * @param {object} o - parameter object
     * @return {string} current value or error message
     */
    user(o) {
        if (o.curVal.length === 0) {
            return 'user preload item not supported in enketo yet';
        }

        return o.curVal;
    },
    /**
     * @param {object} o - parameter object
     * @return {string} current value or evaluated value
     */
    uid(o) {
        if (o.curVal.length === 0) {
            return this.form.model.evaluate(
                'concat("uuid:", uuid())',
                'string'
            );
        }

        return o.curVal;
    },
};