/**
* KeyValueCollection represents keys and values parsed from
* manifests and tag files. Manifest data should use the file path
* as the key and the checksum as the value. There should be only
* one entry for each file in a manifest.
*
* Tag file data should use the tag name as the key and the tag
* value as the value. Each tag may appear multiple times in a tag
* file, so tag names may have multiple values. This collection preserves
* the order of those values.
*/
class KeyValueCollection {
constructor() {
this.items = {};
}
/**
* Adds a key with the specified value to the collection.
* You may add a key multiple times, and all values will be
* stored in the order they were added.
*
* @param {string} key
* @param {string} value
*/
add(key, value) {
if (!this.items.hasOwnProperty(key)) {
this.items[key] = [];
}
this.items[key].push(value);
}
/**
* first returns the first value for the key, or null
* if the key is not found. Use this to when reading data
* parsed from manifests.
*
* @param {string} key
*
* @returns {*} The first value associated with the specified
* key, or null.
*/
first(key) {
var match = this.items[key];
if (Array.isArray(match)) {
return match[0];
}
return null;
}
/**
* all returns all values for a key as an array of strings,
* or null, which indicates the key is not present at all.
* Use this when reading data parsed from tag files, where tags
* may appear multiple times and have multiple values.
*
* @param {string} key
*
* @returns {Array} List of associated keys, or null if key is not found.
*/
all(key) {
if (this.items.hasOwnProperty(key)) {
return this.items[key];
}
return null;
}
/**
* keys returns all keys in the collection
*
* @returns {Array}
*/
keys() {
return Object.keys(this.items);
}
/**
* Returns all the keys in sorted order.
*
* @returns {Array}
*/
sortedKeys() {
return this.keys().sort();
}
}
module.exports.KeyValueCollection = KeyValueCollection;