SAP Fiori开发中的JavaScript基础知识16 - 用JavaScript实现ABAP的内表效果

1. ABAP内表

内表是ABAP编程过程中最常用的一种数据类型，下面是一个简单的内表程序，也即使用内表存储多个"人名数据"。

先定义结构ts_person，并基于结构定义内表变量lt_people，然后通过insert语句为内表赋值。

javascript 复制代码

REPORT ztest_interal_table.

TYPES: BEGIN OF ts_person,
         first_name TYPE string,
         last_name  TYPE string,
       END OF ts_person.

DATA: ls_person TYPE ts_person,
      lt_people TYPE STANDARD TABLE OF ts_person.

ls_person-first_name = 'Mick'.
ls_person-last_name  = 'Wang'.
INSERT ls_person INTO TABLE lt_people.

ls_person-first_name = 'Tom'.
ls_person-last_name  = 'li'.
INSERT ls_person INTO TABLE lt_people.

ls_person-first_name = 'Jone'.
ls_person-last_name  = 'Xu'.
INSERT ls_person INTO TABLE lt_people.

LOOP AT lt_people ASSIGNING FIELD-SYMBOL(<ls_person>).
  WRITE: / <ls_person>-first_name, <ls_person>-last_name.
ENDLOOP.

2. JavaScript的等价实现

如何用JavaScript进行等价实现呢？

首先让我们声明一个构造函数Person，用于定义类型；然后定义一个数组people来存储数据；数组中存储的是基于Person生成的对象实例。

javascript 复制代码

// construct Person as object with the fields firstName and lastName
function Person(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
}

// create an arrary to store different people
let people = [];
people.push(new Person("Mick", "Wang"));
people.push(new Person("Tom", "Li"));
people.push(new Person("Jone", "Xu"));

// loop over the arrary and print out
for (let person of people) {
    console.log(person.firstName + " " + person.lastName);
}

如果要进行类比的话，可以有如下的对应关系：

JavaScript的function Person()实现了ABAP中定义的数据结构ts_person；

JavaScript的数组people实现了ABAP中内表变量lt_people的功能；

JavaScript中数组的push()方法为数组赋值，实现了ABAP中Insert关键字向内表插入数据的效果。

3. 小结

本文通过一个小的示例程序，展示了用JavaScript的函数和数组实现ABAP中内表的效果。希望本文对你有帮助！