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VisualizaçõesJavaScript Array Map Function not working as expected
I have got an issue with the Array.map function not working as I would expect. I have simplified my example below, I just want to get an understanding of where I am going wrong.
So I have the following code below:
console.log(this.reportTestData)
let data = this.reportTestData.map((row) => {
return [ 1 , 2, 3]
});
console.log(data)
return data
From the first console.log, this.reportTestData is an array containing 92 objects, the content of each object is irrelevant:
So from the code, I would expect the map function to run over the array 92 times, and return a new array ( [1,2,3] ) for each element. Leaving me with an array of 92 elements, which each element is a [1,2,3] array. However that is not what I get.
Instead I am getting an array of 92 elements, but each element is completely empty.
I also tried to return objects from the map function instead:
console.log(this.reportTestData)
let data = this.reportTestData.map((col) => {
return { test : 1 }
});
console.log(data)
return data
However I still get empty objects returned with no properties:
Any help that could be offered would be greatly appreciated, as I cannot see where I am making a mistake.
2 Respostas
Responde à pergunta0
Works for me
const reportTestData = new Array(12).fill(0);
let data1 = reportTestData.map((row) => {
return [ 1 , 2, 3]
});
console.log(data1)
let data2 = reportTestData.map((row) => {
return { test : 1 }
});
console.log(data2)
0
I tried for 10 items in an array, and as you may see there are 10-pieces of [1,2,3] ... so map function is working fine, as par I can say.
let reportTestData = [1,2,3,4,5,6,7,8,9,10]
console.log(reportTestData)
let data = reportTestData.map((item) => [ 1 , 2, 3]);
console.log(data)Now trying again with 10-objects in an array:
let reportTestData = [{},{},{},{},{},{},{},{},{},{}]
console.log(reportTestData)
let data = reportTestData.map((item) => [ 1 , 2, 3]);
console.log(data)Again map function of Arrays works fine, so you need to check what wrong you are doing in your code.