Function isStringAnd

Executes a type guard for the string type prior to testing a condition that requires an input of string type, returning true only if both the type check and condition pass.

Remarks

This is especially useful in pipelines where the TS type checker would not detect that a type guard had been applied using other alternatives.

Example

import * as G from "flurp/guard";
import * as L from "flurp/logic";
import * as S from "flurp/string";

const goodStartW = G.isStringAnd(S.startsWith("w"));
goodStartW("weasel");                // true
goodStartW("a weasel");              // false
goodStartW(/a weasel/);              // false

const badStartW = L.both(G.isString, S.startsWith("w"));
badStartW(/a weasel/);         // TS compiler will not recognize G.isString as a type guard.