+ if (typeof name !== 'string') {
+ throw new TypeError('name argument must be a string')
+ }
+ if (typeof name === 'string' && name.trim().length === 0) {
+ throw new TypeError('name argument must not be an empty string')
+ }
+ if (typeof fn !== 'function') {
+ throw new TypeError('fn argument must be a function')
+ }
+ this.taskFunctions.set(name, fn)