CanvasJS文档X轴数值转月份及PHP DateTime转该数值咨询

Great question! Let's break this down into two clear parts to solve your problem:

1. Understanding & Converting the Numeric X-Values to Months #

Those long numbers like 1451586600000 are Unix timestamps in milliseconds (standard Unix timestamps count seconds since the epoch, so this is just that value multiplied by 1000).

If you want to convert them manually in JavaScript: #

Use the native Date object to parse the timestamp, then format it to the month/year style you need. For example:

const canvasJsTimestamp = 1451586600000;
const date = new Date(canvasJsTimestamp);
// Format to "Jan 2016" style
const formattedMonth = date.toLocaleString('en-US', { 
  month: 'short', 
  year: 'numeric' 
});
console.log(formattedMonth); // Outputs "Jan 2016"

As you already noted, CanvasJS handles this formatting automatically when you configure your chart with:

xValueType: "dateTime",
xValueFormatString: "MMM YYYY"

This tells the chart to interpret the numeric values as date/time and render them directly in the month-year format.

2. Converting a PHP DateTime Object to CanvasJS's Numeric X-Value #

To get the same millisecond-based timestamp from a PHP DateTime object, convert it to a Unix timestamp (in seconds) and multiply by 1000. Here are a couple of reliable approaches:

Basic conversion (for dates without milliseconds): #

// Create your DateTime object
$myDate = new DateTime('2016-01-01');

// Method 1: Use getTimestamp()
$millisecondTimestamp = $myDate->getTimestamp() * 1000;

// Method 2: Use format() to get the Unix timestamp in seconds
$millisecondTimestamp = (int)$myDate->format('U') * 1000;

For dates with milliseconds: #

If your DateTime includes millisecond precision, capture the microseconds and convert them to milliseconds like this:

$myDate = new DateTime('2016-01-01 09:30:45.123');
// 'U' gives seconds, 'u' gives microseconds; divide by 1000 to get milliseconds
$millisecondTimestamp = (int)$myDate->format('Uu') / 1000;

This will give you the exact numeric format CanvasJS expects for its multi-series area chart.

内容的提问来源于stack exchange，提问作者dydx