/**
 * **!Do not construct directly!**
 *
 * **!Only static methods because it gets serialized!**
 *
 * This represents the "canonical" version for an extension identifier. Extension ids
 * have to be case-insensitive (due to the marketplace), but we must ensure case
 * preservation because the extension API is already public at this time.
 *
 * For example, given an extension with the publisher `"Hello"` and the name `"World"`,
 * its canonical extension identifier is `"Hello.World"`. This extension could be
 * referenced in some other extension's dependencies using the string `"hello.world"`.
 *
 * To make matters more complicated, an extension can optionally have an UUID. When two
 * extensions have the same UUID, they are considered equal even if their identifier is different.
 */
export class ExtensionIdentifier {
    constructor(value) {
        this.value = value;
        this._lower = value.toLowerCase();
    }
    /**
     * Gives the value by which to index (for equality).
     */
    static toKey(id) {
        if (typeof id === 'string') {
            return id.toLowerCase();
        }
        return id._lower;
    }
}