tm.Terms is not a constructor when running examples/get_terms.js and creating_corpus.js

[Symbolk]

var terms = new tm.Terms( corpus );
            ^

TypeError: tm.Terms is not a constructor
    at Object.<anonymous> (D:\coding\pku\text-miner\examples\get_terms.js:10:13)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
    at Function.Module._load (internal/modules/cjs/loader.js:531:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:754:12)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)