rousseau.filter is not a function

[Kyaw-Zin-Thant]

rousseau.filter(function(word) {
^

TypeError: rousseau.filter is not a function
at Object. (/Users/kyawzinthant/spcheck/index.js:9:18)
at Module._compile (internal/modules/cjs/loader.js:1151:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1171:10)
at Module.load (internal/modules/cjs/loader.js:1000:32)
at Function.Module._load (internal/modules/cjs/loader.js:899:14)
at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)
at internal/main/run_main_module.js:17:47