How does Mini Program make the js file of a custom component receive the parameters of the parent?

recently made a Mini Program, because several different pages have list information, so the list is used as a common component list. You want to pass the interface api of the current page to the list common component when referencing on different pages, so that the list will display different data on different pages. However, when passing parameters, the wxml template file of the list common component can receive the parameters passed by the parent component, and the js file can not get the parameters. Tried that this.properties.url received a null value. Relations tried and couldn"t find it. Ask the Great God for advice

the following is the parent index.wxml file

index.js

list.wxml

list.js

Big Boss, please take a look at what"s wrong. Thank you

.
Javascript
Mar.19,2021

there is no such thing as this.properties.url in Mini Program. This is a bit the same as vue's idea, only this.data.url. There is an observer to indicate the response function when the attribute value is changed. These are all

in the document. 
properties: {
    url:{
      type:String,
      value:'',
      observer: function (newVal, oldVal) {
        console.log(newVal, oldVal) 
        console.log(this.data.url)
       }
    }
  }

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e4767d-44c34.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e4767d-44c34.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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