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时刻js日期时间比较

momentjs javascript

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Hackbrew · 技术社区 · 8 年前

我正在从一个javascript函数调用一个api,该函数正确地返回json响应。但是,当单步执行json响应时,当我使用 moment().isSameOrBefore . 我对javascript相当陌生,尤其是node的moment包。

基本上,我想确定哪个预测潮汐最接近执行此函数时的当前时间。这是正确的使用 力矩().IsSameorFore parameter和/或我应该修改代码以进行不同的操作吗?

以下是json:

{ "predictions" : [ {"t":"2018-06-08 03:06", "v":"3.795", "type":"H"},{"t":"2018-06-08 09:25", "v":"0.443", "type":"L"},{"t":"2018-06-08 15:51", "v":"3.884", "type":"H"},{"t":"2018-06-08 22:01", "v":"0.778", "type":"L"} ]}

这是我的功能:

const getTide = require('./modules/getTide.js');

var moment = require('moment');

async function testMod() {
    await getTide.getQuote().then(function(value){
        const parsedData = JSON.parse(value);       
        let text = " "; 
        // This loop steps through the JSON response row by row to test the data
        var i;
        for (i = 0; i < parsedData.predictions.length; i++) { 
            text += 'Record #' + i + ' = ' + parsedData.predictions[i].t + " " + parsedData.predictions[i].v + " " + parsedData.predictions[i].type + " - ";            
            let curDateTime = moment().format('LLL');           
            let theDate = moment(parsedData.predictions[i].t).format('LLL'); 
            let fromNow = moment(parsedData.predictions[i].t).fromNow(); 
            if (parsedData.predictions[i].type === "H") {
                    console.log('High tide for ' + parsedData.predictions[i].t + ', at ' + parsedData.predictions[i].v + ' vertical Feet. ');                                  
                    if (moment(theDate).isSameOrBefore(curDateTime)) {
                       console.log('It is currently ' + curDateTime + ' and that high tide was ' + fromNow);
                    } else {
                       console.log('It is currently ' + curDateTime + ' and that high tide is ' + fromNow + ' from now!');  
                    }                   
                  } else {
                    console.log('Low tide for ' + parsedData.predictions[i].t + ', at ' + parsedData.predictions[i].v + ' vertical Feet. ');
                    if (moment(theDate).isSameOrBefore(curDateTime)) {
                       console.log('It is currently ' + curDateTime + ' and that low tide was ' + fromNow);
                    } else {
                       console.log('It is currently ' + curDateTime + ' and that low tide is ' + fromNow + ' from now!');   
                    }               
                  }     
        }
    }, function(error){
        console.log("problem");
    });
}

testMod();

1 回复 | 直到 8 年前

1

aStewartDesign 8 年前

我认为问题的一部分是您使用格式化字符串来创建矩实例,而不是仅仅使用矩实例本身。所以不要这样做:

let curDateTime = moment().format('LLL');           
let theDate = moment(parsedData.predictions[i].t).format('LLL'); 
// ...
moment(theDate).isSameOrBefore(curDateTime);

尝试:

let curDateTime = moment();
let theDate = moment(parsedData.predictions[i].t);
// ...
theDate.isSameOrBefore(curDateTime); // because theDate is now a moment instance, you can call this function on it

当使用“时刻”时,将日期时间存储为矩实例始终是一个好主意,直到您需要将它们显示给用户为止,然后您可以继续这样做:

theDate.format('LLL');

我想你得到的警告是因为你试图用moment抱怨的'lll'格式的字符串创建一个moment实例(“deprecation warning:value provided is not in a recognized rfc2822 or iso format.”是我看到的警告。如果要分析这些格式,还必须指定格式:

moment('September 4, 1986 8:30 PM', 'LLL').format('YYYY-MM-DD H:mm'); // won't complain