Fabric.js 保存自定义属性

<canvas id="c" width="500" height="400" style="border: 1px solid #ccc;"></canvas>
<button onclick="handleToJSON()">toJSON</button>

<script>
  let canvas = new fabric.Canvas('c')

  let rect = new fabric.Rect({
    width: 30,
    height: 30,
    top: 10,
    left: 10,
    my_id: 'rect01'
  })

  canvas.add(rect)

  function handleToJSON() {
    console.log(canvas.toJSON()) // 序列化，输出JSON
  }
</script>

// 省略部分代码
let canvas = new fabric.Canvas('c')

let rect = new fabric.Rect({
  width: 30,
  height: 30,
  top: 10,
  left: 10,
  my_id: 'rect01'
})

canvas.add(rect)

function handleToJSON() {
  console.log(canvas.toJSON(['my_id'])) // 序列化，输出JSON
}