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isError

isError :: a → Boolean
Evaluates whether the given value is of type Error​
import isError from 'deep-waters/isError';
​
const err = new Error('foo');
​
isError(err); // → true
isError(anythingElse); // → false
isError, like any other type validator, is mostly used in composed validators:
import isString from 'deep-waters/isString';
import matchesPattern from 'deep-waters/matchesPattern';
​
const isEmail = compose(
isString,
matchesPattern(/^\w+([.-]?\w+)*@\w+([.-]?\w+)*(\.\w{2,3})+$/),
);
isError is built on top of ofClass validator and rely on Object.prototype.toString to check on the received value type in order to avoid typeof weird behaviours and encouraging a runtime strict type validation.