fix: readable identifier (#1024)

Author: alexander-akait

src/index.js

@@ -165,7 +165,9 @@ class MiniCssExtractPlugin {
  }
 
  identifier() {
- return `css|${this._identifier}|${this._identifierIndex}|${this.layer}|${this.supports}|${this.media}}}`;
+ return `css|${this._identifier}|${this._identifierIndex}|${
+ this.layer || ""
+ }|${this.supports || ""}|${this.media}}}`;
  }
 
  /**
@@ -175,7 +177,9 @@ class MiniCssExtractPlugin {
  readableIdentifier(requestShortener) {
  return `css ${requestShortener.shorten(this._identifier)}${
  this._identifierIndex ? ` (${this._identifierIndex})` : ""
- }`;
+ }${this.layer ? ` (layer ${this.layer})` : ""}${
+ this.supports ? ` (supports ${this.supports})` : ""
+ }${this.media ? ` (media ${this.media})` : ""}`;
  }
 
  // eslint-disable-next-line class-methods-use-this