discounts-minapp/utils/tool.js

//防抖debounce代码：
export function debounce(fn, delay = 500) {
	var timeout = null; // 创建一个标记用来存放定时器的返回值
	return function(e) {
		// 每当用户输入的时候把前一个 setTimeout clear 掉
		clearTimeout(timeout);
		// 然后又创建一个新的 setTimeout, 这样就能保证interval 间隔内如果时间持续触发，就不会执行 fn 函数
		timeout = setTimeout(() => {
			fn.apply(this, arguments);
		}, delay);
	};
}

// 时间戳转换
export function timestampToDate(timestamp) {
	// 定义日期格式对应的映射  
	const date = new Date(timestamp);
	const year = date.getFullYear();
	const month = String(date.getMonth() + 1).padStart(2, '0');
	const day = String(date.getDate()).padStart(2, '0');
	const hours = String(date.getHours()).padStart(2, '0');
	const minutes = String(date.getMinutes()).padStart(2, '0');
	const seconds = String(date.getSeconds()).padStart(2, '0');
	return `${year}-${month}-${day} ${hours}:${minutes}:${seconds}`;
}


// 返回两个经纬度之间的距离 单位米
const earthDistance = function(location1, location2) {
	const lat1 = parseFloat(location1.lat);
	const lng1 = parseFloat(location1.lng);
	const lat2 = parseFloat(location2.lat);
	const lng2 = parseFloat(location2.lng);

	const EARTH_RADIUS = 6378137.0; //单位M
	const PI = Math.PI;

	function getRad(d) {
		return d * PI / 180.0;
	}

	let f = getRad((lat1 + lat2) / 2);
	let g = getRad((lat1 - lat2) / 2);
	let l = getRad((lng1 - lng2) / 2);

	let sg = Math.sin(g);
	let sl = Math.sin(l);
	let sf = Math.sin(f);

	let s, c, w, r, d, h1, h2;
	let a = EARTH_RADIUS;
	let fl = 1 / 298.257;

	sg = sg * sg;
	sl = sl * sl;
	sf = sf * sf;

	s = sg * (1 - sl) + (1 - sf) * sl;
	c = (1 - sg) * (1 - sl) + sf * sl;

	w = Math.atan(Math.sqrt(s / c));
	r = Math.sqrt(s * c) / w;
	d = 2 * w * a;
	h1 = (3 * r - 1) / 2 / c;
	h2 = (3 * r + 1) / 2 / s;

	return d * (1 + fl * (h1 * sf * (1 - sg) - h2 * (1 - sf) * sg));
};


//rpx转换px  px=rpx * (屏幕宽度 / 750)
export const rpxTopx = function(rpx) {
	let width = uni.getWindowInfo().screenWidth
	let px = rpx * (width / 750);
	return px
}

/**
 * 腾讯经纬度转百度地图经纬度
 * @param {Object} lng
 * @param {Object} lat
 */
export function qqMapTransBMap(lng, lat) {
	let x_pi = (3.14159265358979324 * 3000.0) / 180.0
	let x = lng
	let y = lat
	let z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi)
	let theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi)
	let lngs = z * Math.cos(theta) + 0.0065
	let lats = z * Math.sin(theta) + 0.006
	return {
		lng: lngs,
		lat: lats,
	}
}
/**
 * 百度地图经纬度转腾讯地图经纬度
 * @param {Object} lng
 * @param {Object} lat
 */
export function bMapTransQQMap(lng, lat) {
	let x_pi = (3.14159265358979324 * 3000.0) / 180.0
	let x = lng - 0.0065
	let y = lat - 0.006
	let z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi)
	let theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi)
	let lngs = z * Math.cos(theta)
	let lats = z * Math.sin(theta)
	return {
		lng: lngs,
		lat: lats,
	}
}

/**
 *  将百度坐标(DB-09)转为GCJ-02(火星坐标):
 */
export function transformFromBaiduToGCJ(latitude, longitude) {
	var xPi = 3.14159265358979323846264338327950288 * 3000.0 / 180.0;

	var x = longitude - 0.0065;
	var y = latitude - 0.006;
	var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * xPi);
	var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * xPi);
	var a_latitude = z * Math.sin(theta);
	var a_longitude = z * Math.cos(theta);

	return {
		latitude: a_latitude,
		longitude: a_longitude
	};
}

/**
 *  判断经纬度是否超出中国境内
 */
function isLocationOutOfChina(latitude, longitude) {
	if (longitude < 72.004 || longitude > 137.8347 || latitude < 0.8293 || latitude > 55.8271)
		return true;
	return false;
}

function transformLatWithXY(x, y) {
	var pi = 3.14159265358979324;
	var lat = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
	lat += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
	lat += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
	lat += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
	return lat;
}

function transformLonWithXY(x, y) {
	var pi = 3.14159265358979324;
	var lon = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
	lon += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
	lon += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
	lon += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
	return lon;
}


/**
 * 谷歌地图经纬度转gcj02经纬度
 * @param {Object} lng
 * @param {Object} lat
 */

export function transformFromWGSToGCJ(latitude, longitude) {
	var lat = "";
	var lon = "";
	var ee = 0.00669342162296594323;
	var a = 6378245.0;
	var pi = 3.14159265358979324;

	if (isLocationOutOfChina(latitude, longitude)) {
		lat = latitude;
		lon = longitude;
	} else {
		var adjustLat = transformLatWithXY(longitude - 105.0, latitude - 35.0);
		var adjustLon = transformLonWithXY(longitude - 105.0, latitude - 35.0);
		var radLat = latitude / 180.0 * pi;
		var magic = Math.sin(radLat);
		magic = 1 - ee * magic * magic;
		var sqrtMagic = Math.sqrt(magic);
		adjustLat = (adjustLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
		adjustLon = (adjustLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
		latitude = latitude + adjustLat;
		longitude = longitude + adjustLon;
	}
	return {
		latitude: latitude,
		longitude: longitude
	};

}