amap-shapes-generator/lib/Utils.js

/*
    205.395583333332 = 205°23'44.1"
    1，直接读取"度"：205
    2，(205.395583333332-205)*60=23.734999999920 得到"分"：23
    3，(23.734999999920-23)*60=44.099999995200 得到"秒"：44.1
    return string,
*/
function latLngDecimalToDegrees(decimal) {
    let absDecimal = Math.abs(decimal);
    let isNegative = Math.abs(decimal) != decimal;
    let d = Math.floor(absDecimal); //度
    let m = Math.floor((absDecimal - d) * 60); //分
    let s = Math.round((absDecimal - d) * 3600 % 60); //秒
    if (s == 60) {
        s = 0;
        m++;
    }
    if (m == 60) {
        m = 0;
        d++;
    }
    //d = ('000'+d).slice(-3);                   // left-pad with leading zeros
    const mm = ('00' + m).slice(-2); // left-pad with leading zeros
    const ss = ('00' + s).slice(-2);
    //if (s<10) s = '0' + s;                     // left-pad with leading zeros (note may include decimals)
    return (isNegative ? "-" : "") + d + '°' + mm + "′" + ss + '″';
}
/*
    Decimal Degrees = Degrees + minutes/60 + seconds/3600
    例：57°55'56.6" =57+55/60+56.6/3600=57.9323888888888
    return Float or NaN
*/
function latLngDegreesToDecimal(degreesStr) {
    let degreesArr = degreesStr.split("°");
    let degrees = parseInt(degreesArr[0]);
    let isNegative = Math.abs(degrees) != degrees;
    if (degreesArr.length == 1) {
        return degrees;
    }
    let minutesArr = degreesArr[1].split("′");
    let minutes = parseInt(minutesArr[0]);
    if (minutesArr.length == 1) {
        return parseFloat((isNegative ? "-" : "") + (Math.abs(degrees) + Math.abs(minutes) / 60));
    }
    let secondsStr = minutesArr[1];
    let secondsArr = secondsStr.split('″');
    let seconds = parseFloat(secondsArr[0]);
    return parseFloat((isNegative ? "-" : "") + (Math.abs(degrees) + Math.abs(minutes) / 60 + Math.abs(seconds) / 3600));
}
function isObject(arg) {
    return typeof arg === 'object' && arg !== null;
}
function isUndefined(arg) {
    return arg === void 0;
}
function isString(arg) {
    return typeof arg === 'string';
}
function hasLine(obj) {
    return (isObject(obj)
        && isSafeString(obj.lat)
        && isSafeString(obj.lng));
}
function isSafeString(arg) {
    if (isUndefined(arg)) {
        return false;
    }
    if (!isString(arg)) {
        return false;
    }
    if (arg.length == 0) {
        return false;
    }
    return true;
}
function hasPoint(obj) {
    return (isObject(obj)
        && isSafeString(obj.lat)
        && isSafeString(obj.lng));
}
module.exports = {
    latLngDecimalToDegrees,
    latLngDegreesToDecimal,
    isObject,
    isUndefined,
    isString,
    isSafeString,
    hasLine,
    hasPoint
};