First sorry for my english.

I have a font 'Merel'. I use it in my web-app in two weights 500 and 300.

With PreloadJS 1.0.0 this JS code:

var fldr = new createjs.FontLoader({
 src: [
 "/fonts/merel/Merel-Medium.woff2",
 "/fonts/merel/Merel-Light.woff2"
 ],
 type "font"
 }, true);
fldr.load();

produces this CSS:

@font-face {
 font-family: 'Merel';
 font-style: normal;
 font-weight: 300;
 src: local('Merel Light'), url('/fonts/merel/Merel-Light.woff2') format('woff2');
}
@font-face {
 font-family: 'Merel';
 font-style: normal;
 font-weight: medium;
 src: local('Merel Medium'), url('/fonts/merel/Merel-Medium.woff2') format('woff2');
}

But regarding to MDN the medium is an incorrect value for the font-weight property. And I see in the console of my Chromium 64.0.3254.0 and Firefox Nightly 59.0a1 that Merel-Medium is loaded only after I make a visible element that uses it. And also I see that "Flash Of Unstyled Text" in that moment.

This is also happened when I specify 'medium' as a weight in a css or object definition.

{
 src: [ {
 src: "url(/fonts/merel/Merel-Medium.woff2) format('woff2')",
 family: "Merel",
 weight: "medium",
 style: "normal"
 }, /*....*/ ],
 type: "font"
}

When I specify font-weight as the '500' then the font preloads correct. But in that case I can not use short array definition as a list of files.

The MDN says that correct font weights are: normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
Also the PHPStorm tells me that 'medium' is invalid value for the 'font-weight' property when I try to use it in my styles.