the parent component gets the data from the interface and passes it to the child component through props, passing on a nested array similar to a [1mem2prime3]. Both the parent component and the child component can console.log (a) and a [0], but accessing a0 will be a undefine (not an error report). The parent component and the child component can both get the data from the interface and pass it to the child component through the interface, passing it to the child component through the interface and passing it to the child component through the interface. It just cannot be displayed after the front end refreshes the page)
subcomponents console:
console.log (this.RoadPerc)
console.log (this.RoadPerc [0])
console.log (this.RoadPerc0)
because what I write at the front end is a few buttons click to switch to display the data in the array, refresh the page and click on the data