Add function to read first 'n' lines of file as text.

1 files changed, 16 insertions, 0 deletions

diff --git a/uploader/static/js/files.js b/uploader/static/js/files.js
new file mode 100644
index 0000000..c1dedad
--- /dev/null
+++ b/uploader/static/js/files.js
@@ -0,0 +1,16 @@
+var read_first_n_lines = (fileelement, count, process_content_fns) => {
+    var thefile = fileelement.files[0];
+    var reader = new FileReader();
+    if(typeof thefile !== "undefined" && thefile !== null) {
+        reader.addEventListener("load", (event) => {
+            var content = event
+                .target
+                .result
+                .split("\n")
+                .slice(0, count)
+                .map((line) => {return line.trim("\r");});
+            process_content_fns.forEach((fn) => {fn(content);});
+        });
+        reader.readAsText(thefile);
+    }
+};