The array cannot be obtained when express submits data with post

  node.js, question

When express submitted data with post, the array could not be obtained. The array was put in json and passed to the background. But req.body did not get an array

This is the front-end code
前端操作

This is the data acquired in the background.
图片描述

The key of the array changed to “tt[]”

This is the problem. Ask the great god to point out what is wrong

Add parametertraditional: trueTry