Add file names in a column when using fread

I have several .txt files that I am importing with the following code:

files = list.files(pattern="*.txt")%>% 
     map_df(~fread(.))

Each file has several rows and columns, and I want to add an id row with the file name. So if the files were called A-ML201.txt and A-YH248, etc., I would get the following. The file names need to repeat since each file has multiple rows:

ID         col1    col2 
A-ML201     2       67
A-ML201     4       29
A-ML201     1       90
A-YH248     23      2
A-YH248     12      17
A-YH248     8       57

I have tried a few solutions from this thread: How to import multiple .csv files at once?. But keep getting errors, maybe because they are .txt files? I tried replacing read.csv with read.table. I am new to this kind of thing so any help is greatly apppreciated!

>Solution :

We could pass a named vector and then use .id

library(purrr)
library(dplyr)
library(stringr)
library(data.table)
files <- list.files(path = "path/to/your/folder", 
    pattern="\\.txt", full.names = TRUE)
names(files) <- str_remove(basename(files), "\\.txt")
map_dfr(files, fread, .id = 'ID')