Chart/api/flow.ts

/**
 * Copyright (c) 2017 ~ present NAVER Corp.
 * billboard.js project is licensed under the MIT license
 */
import {isDefined, isTabVisible, isValue, parseDate} from "../../module/util";

export default {
	/**
	 * Flow data to the chart.<br><br>
	 * By this API, you can append new data points to the chart.
	 * @function flow
	 * @instance
	 * @memberof Chart
	 * @param {object} args The object can consist with following members:<br>
	 *
	 *    | Key | Type | Description |
	 *    | --- | --- | --- |
	 *    | json | Object | Data as JSON format (@see [data․json](Options.html#.data%25E2%2580%25A4json)) |
	 *    | rows | Array | Data in array as row format (@see [data․rows](Options.html#.data%25E2%2580%25A4json)) |
	 *    | columns | Array | Data in array as column format (@see [data․columns](Options.html#.data%25E2%2580%25A4columns)) |
	 *    | to | String | The lower x edge will move to that point. If not given, the lower x edge will move by the number of given data points |
	 *    | length | Number | The lower x edge will move by the number of this argument |
	 *    | duration | Number | The duration of the transition will be specified value. If not given, transition.duration will be used as default |
	 *    | done | Function | The specified function will be called when flow ends |
	 *
	 * - **NOTE:**
	 *   - If json, rows and columns given, the data will be loaded.
	 *   - If data that has the same target id is given, the chart will be appended.
	 *   - Otherwise, new target will be added. One of these is required when calling.
	 *   - If json specified, keys is required as well as data.json.
	 * 	 - If tab isn't visible(by evaluating `document.hidden`), will not be executed to prevent unnecessary work.
	 * @example
	 * // 2 data points will be apprended to the tail and popped from the head.
	 * // After that, 4 data points will be appended and no data points will be poppoed.
	 * chart.flow({
	 *  columns: [
	 *    ["x", "2018-01-11", "2018-01-21"],
	 *    ["data1", 500, 200],
	 *    ["data2", 100, 300],
	 *    ["data3", 200, 120]
	 *  ],
	 *  to: "2013-01-11",
	 *  done: function () {
	 *    chart.flow({
	 *      columns: [
	 *        ["x", "2018-02-11", "2018-02-12", "2018-02-13", "2018-02-14"],
	 *        ["data1", 200, 300, 100, 250],
	 *        ["data2", 100, 90, 40, 120],
	 *        ["data3", 100, 100, 300, 500]
	 *      ],
	 *      length: 2,
	 *      duration: 1500
	 *    });
	 *  }
	 * });
	 */
	flow(args): void {
		const $$ = this.internal;
		let data;
		let domain;
		let length: number = 0;
		let tail = 0;
		let diff;
		let to;

		if (args.json || args.rows || args.columns) {
			data = $$.convertData(args);
		}

		if ($$.state.redrawing || !data || !isTabVisible()) {
			return;
		}

		const notfoundIds: string[] = [];
		const orgDataCount = $$.getMaxDataCount();
		const targets = $$.convertDataToTargets(data, true);
		const isTimeSeries = $$.axis.isTimeSeries();

		// Update/Add data
		$$.data.targets.forEach(t => {
			let found = false;

			for (let i = 0; i < targets.length; i++) {
				if (t.id === targets[i].id) {
					found = true;

					if (t.values[t.values.length - 1]) {
						tail = t.values[t.values.length - 1].index + 1;
					}

					length = targets[i].values.length;

					for (let j = 0; j < length; j++) {
						targets[i].values[j].index = tail + j;

						if (!isTimeSeries) {
							targets[i].values[j].x = tail + j;
						}
					}

					t.values = t.values.concat(targets[i].values);
					targets.splice(i, 1);
					break;
				}
			}

			!found && notfoundIds.push(t.id);
		});

		// Append null for not found targets
		$$.data.targets.forEach(t => {
			for (let i = 0; i < notfoundIds.length; i++) {
				if (t.id === notfoundIds[i]) {
					tail = t.values[t.values.length - 1].index + 1;

					for (let j = 0; j < length; j++) {
						t.values.push({
							id: t.id,
							index: tail + j,
							x: isTimeSeries ? $$.getOtherTargetX(tail + j) : tail + j,
							value: null
						});
					}
				}
			}
		});

		// Generate null values for new target
		if ($$.data.targets.length) {
			targets.forEach(t => {
				const missing: any[] = [];

				for (let i = $$.data.targets[0].values[0].index; i < tail; i++) {
					missing.push({
						id: t.id,
						index: i,
						x: isTimeSeries ? $$.getOtherTargetX(i) : i,
						value: null
					});
				}

				t.values.forEach(v => {
					v.index += tail;

					if (!isTimeSeries) {
						v.x += tail;
					}
				});

				t.values = missing.concat(t.values);
			});
		}

		$$.data.targets = $$.data.targets.concat(targets); // add remained

		// check data count because behavior needs to change when it"s only one
		// const dataCount = $$.getMaxDataCount();
		const baseTarget = $$.data.targets[0];
		const baseValue = baseTarget.values[0];

		// Update length to flow if needed
		if (isDefined(args.to)) {
			length = 0;
			to = isTimeSeries ? parseDate.call($$, args.to) : args.to;

			baseTarget.values.forEach(v => {
				v.x < to && length++;
			});
		} else if (isDefined(args.length)) {
			length = args.length;
		}

		// If only one data, update the domain to flow from left edge of the chart
		if (!orgDataCount) {
			if (isTimeSeries) {
				diff = baseTarget.values.length > 1 ?
					baseTarget.values[baseTarget.values.length - 1].x - baseValue.x :
					baseValue.x - $$.getXDomain($$.data.targets)[0];
			} else {
				diff = 1;
			}

			domain = [baseValue.x - diff, baseValue.x];
		} else if (orgDataCount === 1 && isTimeSeries) {
			diff = (baseTarget.values[baseTarget.values.length - 1].x - baseValue.x) / 2;
			domain = [new Date(+baseValue.x - diff), new Date(+baseValue.x + diff)];
		}

		domain && $$.updateXDomain(null, true, true, false, domain);

		// Set targets
		$$.updateTargets($$.data.targets);

		// Redraw with new targets
		$$.redraw({
			flow: {
				index: baseValue.index,
				length: length,
				duration: isValue(args.duration) ? args.duration : $$.config.transition_duration,
				done: args.done,
				orgDataCount: orgDataCount,
			},
			withLegend: true,
			withTransition: orgDataCount > 1,
			withTrimXDomain: false,
			withUpdateXAxis: true
		});
	}
};