function Test.is is<T extends Testing>(t: null | undefined): Step<T, unknown> Confirm that value returned by previous test step is of given type. Optionally, confirms other predicates about the value. Type Parameters T extends Testing Parameters t: null | undefined Return Type Step<T, unknown> is<T extends Testing>(t: "string",expected?: string,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "string" optional expected: string Return Type Step<T, unknown> is<T extends Testing>(t: "number",expected?: number,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "number" optional expected: number Return Type Step<T, unknown> is<T extends Testing>(t: "bigint",expected?: bigint,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "bigint" optional expected: bigint Return Type Step<T, unknown> is<T extends Testing>(t: "boolean",expected?: string,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "boolean" optional expected: string Return Type Step<T, unknown> is<T extends Testing>(t: "symbol",expected?: symbol,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "symbol" optional expected: symbol Return Type Step<T, unknown> is<T extends Testing>(t: "function",expectedName?: string,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "function" optional expectedName: string Return Type Step<T, unknown> is<T extends Testing>(t: "object",expectedConstructorName?: string,): Step<T, unknown> Type Parameters T extends Testing Parameters t: "object" optional expectedConstructorName: string Return Type Step<T, unknown> is<T extends Testing>(t: "object",...steps: Step<T, unknown>[],): Step<T, unknown> Type Parameters T extends Testing Parameters t: "object" ...steps: Step<T, unknown>[] Return Type Step<T, unknown> is<T extends Testing>(proto: { [[Symbol.hasInstance]](_: unknown): boolean; }): Step<T, unknown> Type Parameters T extends Testing Parameters proto: { [[Symbol.hasInstance]](_: unknown): boolean; } Return Type Step<T, unknown>