Save a typed array as a file from the console (add as a snippet in chrome dev tools)

saveTA.js

/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js */
var saveAs=saveAs||function(view){"use strict";if(typeof navigator!=="undefined"&&/MSIE [1-9]\./.test(navigator.userAgent)){return}var doc=view.document,get_URL=function(){return view.URL||view.webkitURL||view},save_link=doc.createElementNS("http://www.w3.org/1999/xhtml","a"),can_use_save_link="download"in save_link,click=function(node){var event=new MouseEvent("click");node.dispatchEvent(event)},is_safari=/Version\/[\d\.]+.*Safari/.test(navigator.userAgent),webkit_req_fs=view.webkitRequestFileSystem,req_fs=view.requestFileSystem||webkit_req_fs||view.mozRequestFileSystem,throw_outside=function(ex){(view.setImmediate||view.setTimeout)(function(){throw ex},0)},force_saveable_type="application/octet-stream",fs_min_size=0,arbitrary_revoke_timeout=500,revoke=function(file){var revoker=function(){if(typeof file==="string"){get_URL().revokeObjectURL(file)}else{file.remove()}};if(view.chrome){revoker()}else{setTimeout(revoker,arbitrary_revoke_timeout)}},dispatch=function(filesaver,event_types,event){event_types=[].concat(event_types);var i=event_types.length;while(i--){var listener=filesaver["on"+event_types[i]];if(typeof listener==="function"){try{listener.call(filesaver,event||filesaver)}catch(ex){throw_outside(ex)}}}},auto_bom=function(blob){if(/^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)){return new Blob(["\ufeff",blob],{type:blob.type})}return blob},FileSaver=function(blob,name,no_auto_bom){if(!no_auto_bom){blob=auto_bom(blob)}var filesaver=this,type=blob.type,blob_changed=false,object_url,target_view,dispatch_all=function(){dispatch(filesaver,"writestart progress write writeend".split(" "))},fs_error=function(){if(target_view&&is_safari&&typeof FileReader!=="undefined"){var reader=new FileReader;reader.onloadend=function(){var base64Data=reader.result;target_view.location.href="data:attachment/file"+base64Data.slice(base64Data.search(/[,;]/));filesaver.readyState=filesaver.DONE;dispatch_all()};reader.readAsDataURL(blob);filesaver.readyState=filesaver.INIT;return}if(blob_changed||!object_url){object_url=get_URL().createObjectURL(blob)}if(target_view){target_view.location.href=object_url}else{var new_tab=view.open(object_url,"_blank");if(new_tab==undefined&&is_safari){view.location.href=object_url}}filesaver.readyState=filesaver.DONE;dispatch_all();revoke(object_url)},abortable=function(func){return function(){if(filesaver.readyState!==filesaver.DONE){return func.apply(this,arguments)}}},create_if_not_found={create:true,exclusive:false},slice;filesaver.readyState=filesaver.INIT;if(!name){name="download"}if(can_use_save_link){object_url=get_URL().createObjectURL(blob);setTimeout(function(){save_link.href=object_url;save_link.download=name;click(save_link);dispatch_all();revoke(object_url);filesaver.readyState=filesaver.DONE});return}if(view.chrome&&type&&type!==force_saveable_type){slice=blob.slice||blob.webkitSlice;blob=slice.call(blob,0,blob.size,force_saveable_type);blob_changed=true}if(webkit_req_fs&&name!=="download"){name+=".download"}if(type===force_saveable_type||webkit_req_fs){target_view=view}if(!req_fs){fs_error();return}fs_min_size+=blob.size;req_fs(view.TEMPORARY,fs_min_size,abortable(function(fs){fs.root.getDirectory("saved",create_if_not_found,abortable(function(dir){var save=function(){dir.getFile(name,create_if_not_found,abortable(function(file){file.createWriter(abortable(function(writer){writer.onwriteend=function(event){target_view.location.href=file.toURL();filesaver.readyState=filesaver.DONE;dispatch(filesaver,"writeend",event);revoke(file)};writer.onerror=function(){var error=writer.error;if(error.code!==error.ABORT_ERR){fs_error()}};"writestart progress write abort".split(" ").forEach(function(event){writer["on"+event]=filesaver["on"+event]});writer.write(blob);filesaver.abort=function(){writer.abort();filesaver.readyState=filesaver.DONE};filesaver.readyState=filesaver.WRITING}),fs_error)}),fs_error)};dir.getFile(name,{create:false},abortable(function(file){file.remove();save()}),abortable(function(ex){if(ex.code===ex.NOT_FOUND_ERR){save()}else{fs_error()}}))}),fs_error)}),fs_error)},FS_proto=FileSaver.prototype,saveAs=function(blob,name,no_auto_bom){return new FileSaver(blob,name,no_auto_bom)};if(typeof navigator!=="undefined"&&navigator.msSaveOrOpenBlob){return function(blob,name,no_auto_bom){if(!no_auto_bom){blob=auto_bom(blob)}return navigator.msSaveOrOpenBlob(blob,name||"download")}}FS_proto.abort=function(){var filesaver=this;filesaver.readyState=filesaver.DONE;dispatch(filesaver,"abort")};FS_proto.readyState=FS_proto.INIT=0;FS_proto.WRITING=1;FS_proto.DONE=2;FS_proto.error=FS_proto.onwritestart=FS_proto.onprogress=FS_proto.onwrite=FS_proto.onabort=FS_proto.onerror=FS_proto.onwriteend=null;return saveAs}(typeof self!=="undefined"&&self||typeof window!=="undefined"&&window||this.content);if(typeof module!=="undefined"&&module.exports){module.exports.saveAs=saveAs}else if(typeof define!=="undefined"&&define!==null&&define.amd!=null){define([],function(){return saveAs})}
var saveTA = (tarr, n) => { let b = new Blob([tarr], {type: 'application/octet-binary'}); return saveAs(b, n);}

Usage:

saveTA(typedArray, 'file.mp4');