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timthedreamvs.DevLarry

String validation

It validates if a substring in a string is a valid string (this is including all types of brackets but no other symbols)

Code
Diff
  • // Using a regex so we can add any other characters needed also
const regex = /^[a-zA-Z {}() \[\] ]+$/;

export const validateString = (input: string, index: number): boolean => {
  const substr = input.substring(index, input.length - index);
  return regex.test(substr);
};
    • export function validateString(input: string, index: number): boolean {
    • const validator = new BracketsValidator();
    • return [...input].splice(index, input.length-index).every(e=>validator.isValidChar(e));
    • }
    • // Using a regex so we can add any other characters needed also
    • const regex = /^[a-zA-Z {}() \[\] ]+$/;
    • class BracketsValidator {
    • private readonly bracketPairs: Record<string, string> = {
    • '{': '}',
    • '[': ']',
    • '(': ')',
    • };
    • private readonly openBrackets: Set<string> = new Set(Object.keys(this.bracketPairs));
    • private readonly closingBrackets: Set<string> = new Set(Object.values(this.bracketPairs));
    • private stack: string[] = [];
    • public isValidChar(char: string): boolean {
    • if (this.isNotBracket(char)) {
    • return true;
    • }
    • if (this.isOpeningBracket(char)) {
    • this.push(char);
    • return true;
    • }
    • if (this.hasMatchFor(char)) {
    • this.pop();
    • return true;
    • }
    • return false;
    • }
    • private push(bracket: string): void {
    • this.stack.push(bracket);
    • }
    • private pop(): string|undefined {
    • return this.stack.pop();
    • }
    • private lastFromStack(): string|undefined {
    • return this.stack.slice(-1)[0];
    • }
    • private hasMatchFor(bracket: string): boolean {
    • const previousBracket: string|undefined = this.lastFromStack();
    • if (undefined === previousBracket) {
    • return false;
    • }
    • const match = this.matchFor(bracket);
    • return previousBracket === match;
    • }
    • private isOpeningBracket(char: string): boolean {
    • return this.openBrackets.has(char);
    • }
    • private isClosingBracket(char: string): boolean {
    • return this.closingBrackets.has(char)
    • }
    • private isNotBracket(char: string): boolean {
    • return !(this.isOpeningBracket(char)||this.isClosingBracket(char));
    • }
    • private matchFor(bracket: string): string {
    • const index: number = Object.values(this.bracketPairs).indexOf(bracket);
    • return Object.keys(this.bracketPairs)[index];
    • }
    • }
    • export const validateString = (input: string, index: number): boolean => {
    • const substr = input.substring(index, input.length - index);
    • return regex.test(substr);
    • };