Get all files inside a folder in a library using REST in SharePoint

Question

I want to Get all files inside a folder in a library using REST in SharePoint.

I have tried this code

var folderUrl = '/attachment/test/1';
var url = _spPageContextInfo.webServerRelativeUrl + "/_api/Web/GetFolderByServerRelativeUrl('" + folderUrl + "')?$expand=Folders,Files";

$.getJSON(url,function(data,status,xhr){

    for(var i = 0; i < data.Files.length;i++){
        console.log(data.Files[i].Name);    
    }

    for(var i = 0; i < data.Folders.length;i++){
        console.log(data.Folders[i].Name);    
    }
});

Answer 1

Two things seems wrong in your code,

1. Folder Url should be 'attachment/test/1'

2. Syntax for reading response should be data.d.Files.results[i].Name

Try below code. ( Tested & Working )

<script type="text/javascript" src="https://code.jquery.com/jquery-1.12.0.min.js"></script>
<script type="text/javascript">
    $(document).ready(function () {
        getFilesFolders();
    });


    function getFilesFolders() {
        var folderUrl = 'attachment/test/1';
        var webUrl = _spPageContextInfo.webAbsoluteUrl;
        var requestHeaders = { "accept": "application/json;odata=verbose" };
        $.ajax({
            url: webUrl + "/_api/web/GetFolderByServerRelativeUrl('" + folderUrl + "')?$expand=Folders,Files",
            contentType: "application/json;odata=verbose",
            headers: requestHeaders,
            success: onSuccess,
            async: false,
            error: onError
        }); function onSuccess(data, request) {
            for (var i = 0; i < data.d.Files.results.length; i++)
            {
                console.log(data.d.Files.results[i].Name);
            }
            for (var i = 0; i < data.d.Folders.results.length; i++) {
                console.log(data.d.Folders.results[i].Name);
            }    

        } function onError(error) {
            alert("Error occurred.");
        }
    }
</script>