mp3tag/out/cli/interpolator.js

A library for reading/writing mp3 tag data

"use strict";
/** This module exports the interpolator class, which can be used to interpolate
 *  parameter strings based on the source filename and tag data, which is useful when
 *  trying to automatically rename a file based on it's tag data or vice versa.
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.Interpolator = void 0;
//TODO: Add more interpolation functionality, like var navigation
// Map of varname -> interpolation function(itp) -> promise[string]
const variables = {
    /** Retrieves the interpolator's source file.
     *
     * @param interpolator the interpolator instance to get the source from
     *
     * @return a promise, which resolves to the interpolator's source file
     */
    'source': async function (interpolator) {
        return interpolator.source;
    }
};
// Lets use $ for now.. I know this isn't optimal for linux though...
const varPrefix = '$';
const varPostfix = '';
class Interpolator {
    tagData;
    /** the file, from which the tagdata has been parsed
     */
    source;
    /** cached variable values to only calculate them once
     */
    varCache = {};
    /** Should be called by the --in task if it receives a file as parameter
     *
     * @param ourceFile the file, from which the tagdata has been parsed
     * @param tagData the parsed tagdata
     */
    constructor(sourceFile, tagData) {
        this.tagData = tagData;
        this.source = sourceFile;
    }
    /** Should be called to interpolate the given string and replace all variables in it
     *
     * @param rawString the string to replace the variables in
     *
     * @return a promise, which resolves to the interpolated string
     */
    async interpolate(rawString) {
        let result = rawString;
        if (!result) {
            return Promise.resolve(result);
        }
        // Preload all referenced variables
        await this.loadVariables(rawString);
        // Replace all occurring variables
        let varName;
        for (varName in variables) {
            const fullVarName = varPrefix + varName + varPostfix;
            result = result.replace(fullVarName, this.varCache[varName]); // now that all variables are preloaded, we can assume that none is undefined
        }
        return result;
    }
    /** Loads all occuring variables into varcache
     *
     * @param rawString the string to load the variables for
     *
     * @return a promise, which resolves when all variables are loaded
     *         into the variable cache. The resolved value are the variable values.
     *         The promise gets rejected if one of the interpolation functions fails
     */
    loadVariables(rawString) {
        const variablePromises = [];
        let varName;
        for (varName in variables) {
            const interpolateFn = variables[varName];
            const fullVarName = varPrefix + varName + varPostfix;
            if (rawString.indexOf(fullVarName) !== -1) {
                if (!this.varCache[varName]) {
                    variablePromises.push(interpolateFn(this).then((value) => {
                        this.varCache[varName] = value;
                        return Promise.resolve(value);
                    }));
                }
            }
        }
        return Promise.all(variablePromises);
    }
}
exports.Interpolator = Interpolator;