// <https://stackoverflow.com/questions/3446170/escape-string-for-use-in-javascript-regex>
function escapeRegExp(str: string) {
    return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}

type FormatterOptions = {
    keyPrefix?: string,
    keySuffix?: string,
    asRegExp?: boolean
}

const defaultOptions: FormatterOptions = {
    keyPrefix : '',
    keySuffix: '',
    asRegExp: true
} 

export function format(templatedString: string, dictionary: { [key: string]: string }, options: FormatterOptions = defaultOptions) {
    let _options = {...defaultOptions, ...options}
    let formattedString = templatedString;
    Object.keys(dictionary).forEach((key) => {
        let regex:RegExp;
        if (options.asRegExp){
            regex = new RegExp(_options.keyPrefix + key + _options.keySuffix, "g")
        } else {
            regex = new RegExp(`${escapeRegExp(_options.keyPrefix + key + _options.keySuffix)}`, "g")
        }
        formattedString = formattedString.replace(regex, dictionary[key])
    })
    return formattedString;
}

export default format;