Angular 7 and arrays pushing two arrays into one array is giving an error of undefined

Question

I need to combine 2 arrays read from an excel file into 2-dimensional array, so I can place it as dataSource of material table.

I have these 2 arrays read from excel using XLSX library:

    reader.onload = (e) => {
      const res = reader.result as string; // This variable contains your file as text
      const lines = res.split('\n'); // Splits you file into lines
      let ids=[];
      let name = [];
      let array:any[][];
      lines.forEach((line, index) => {
        //console.log(line);
        ids.push((line.split(',')[0]));
        name.push(line.split(',')[1]);
        array.push([ids, name])
      });
      console.log(array);
    }

But I keep getting an error on console.log(array):

ERROR TypeError: Cannot read property 'push' of undefined

EDIT:

I changed the code into:

      let name = [];

      lines.forEach((line, index) => {
        //console.log(line);
        ids.push((line.split(',')[0]));
        name.push(line.split(',')[1]);
        array.push(ids, name)
      });
      console.log(array);

The result was like that:

But that's not what I need because it won't work as dataSource on material table.

I think you should assign empty array for your array like that : let array:any[]=[] — every Bit
– every Bit, Commented Mar 22, 2019 at 8:14
Just for the sake of correct tags - its a pure Javascript/Typescript issue. Not related to angular or xlsx — Jonathan Stellwag
– Jonathan Stellwag, Commented Mar 22, 2019 at 8:18

programoholic · Accepted Answer · 2019-03-22 09:15:47Z

1

If I got your problem right... here is the simple way to achieve your requirement.

 let lines = ["1,xx","2,yy","3,zz"];
 let name = [];
 let array = [];
      lines.forEach((line, index) => {
        //console.log(line);
        let obj = { 
        id : line.split(',')[0],
        name : line.split(',')[1]
        };
        
        //ids.push((line.split(',')[0]));
        //name.push(line.split(',')[1]);
        array.push(obj)
      });
      
console.log(array);

edited Mar 22, 2019 at 9:15

answered Mar 22, 2019 at 8:30

programoholic

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