export declare function isFalsyOrWhitespace(str: string | undefined): boolean;
/**
 * Helper to produce a string with a variable number of arguments. Insert variable segments
 * into the string using the {n} notation where N is the index of the argument following the string.
 * @param value string to which formatting is applied
 * @param args replacements for {n}-entries
 */
export declare function format(value: string, ...args: any[]): string;
/**
 * Converts HTML characters inside the string to use entities instead. Makes the string safe from
 * being used e.g. in HTMLElement.innerHTML.
 */
export declare function escape(html: string): string;
/**
 * Escapes regular expression characters in a given string
 */
export declare function escapeRegExpCharacters(value: string): string;
/**
 * Counts how often `character` occurs inside `value`.
 */
export declare function count(value: string, character: string): number;
export declare function truncate(value: string, maxLength: number, suffix?: string): string;
/**
 * Removes all occurrences of needle from the beginning and end of haystack.
 * @param haystack string to trim
 * @param needle the thing to trim (default is a blank)
 */
export declare function trim(haystack: string, needle?: string): string;
/**
 * Removes all occurrences of needle from the beginning of haystack.
 * @param haystack string to trim
 * @param needle the thing to trim
 */
export declare function ltrim(haystack: string, needle: string): string;
/**
 * Removes all occurrences of needle from the end of haystack.
 * @param haystack string to trim
 * @param needle the thing to trim
 */
export declare function rtrim(haystack: string, needle: string): string;
export declare function convertSimple2RegExpPattern(pattern: string): string;
export declare function stripWildcards(pattern: string): string;
export interface RegExpOptions {
    matchCase?: boolean;
    wholeWord?: boolean;
    multiline?: boolean;
    global?: boolean;
    unicode?: boolean;
}
export declare function createRegExp(searchString: string, isRegex: boolean, options?: RegExpOptions): RegExp;
export declare function regExpLeadsToEndlessLoop(regexp: RegExp): boolean;
export declare function regExpContainsBackreference(regexpValue: string): boolean;
export declare function regExpFlags(regexp: RegExp): string;
export declare function splitLines(str: string): string[];
/**
 * Returns first index of the string that is not whitespace.
 * If string is empty or contains only whitespaces, returns -1
 */
export declare function firstNonWhitespaceIndex(str: string): number;
/**
 * Returns the leading whitespace of the string.
 * If the string contains only whitespaces, returns entire string
 */
export declare function getLeadingWhitespace(str: string, start?: number, end?: number): string;
/**
 * Returns last index of the string that is not whitespace.
 * If string is empty or contains only whitespaces, returns -1
 */
export declare function lastNonWhitespaceIndex(str: string, startIndex?: number): number;
export declare function compare(a: string, b: string): number;
export declare function compareSubstring(a: string, b: string, aStart?: number, aEnd?: number, bStart?: number, bEnd?: number): number;
export declare function compareIgnoreCase(a: string, b: string): number;
export declare function compareSubstringIgnoreCase(a: string, b: string, aStart?: number, aEnd?: number, bStart?: number, bEnd?: number): number;
export declare function isLowerAsciiLetter(code: number): boolean;
export declare function isUpperAsciiLetter(code: number): boolean;
export declare function equalsIgnoreCase(a: string, b: string): boolean;
export declare function startsWithIgnoreCase(str: string, candidate: string): boolean;
/**
 * @returns the length of the common prefix of the two strings.
 */
export declare function commonPrefixLength(a: string, b: string): number;
/**
 * @returns the length of the common suffix of the two strings.
 */
export declare function commonSuffixLength(a: string, b: string): number;
/**
 * See http://en.wikipedia.org/wiki/Surrogate_pair
 */
export declare function isHighSurrogate(charCode: number): boolean;
/**
 * See http://en.wikipedia.org/wiki/Surrogate_pair
 */
export declare function isLowSurrogate(charCode: number): boolean;
/**
 * See http://en.wikipedia.org/wiki/Surrogate_pair
 */
export declare function computeCodePoint(highSurrogate: number, lowSurrogate: number): number;
/**
 * get the code point that begins at offset `offset`
 */
export declare function getNextCodePoint(str: string, len: number, offset: number): number;
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