node.js - Javascript / NodeJS: (() => 0) === (() => 0) -

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i'm reading javascript allongé, , in see code supposed return false:

(() => 0) === (() => 0)

when run on commandline (ubuntu 14.04) using nodejs, 3 dots: ..., after cancel using ctrl-c.

i start node.js following command: nodejs, not node. using --harmony doesn't make difference.

node.js version: v0.10.25

why don't result back? thought using nodejs commandline test utility, maybe not idea?

the simple answer why returns false because though functions same thing , same, initialized in 2 different memory locations (for objects functions, plain objects, , arrays, strict equality operator === checks memory location of object.)

also, if you're going use node.js, have make sure interpreting ecmascript6 (otherwise, () => 0 not valid es5, default node.js).

you can use --harmony flag:

node --harmony app.js

see question "what node --harmony do?" more info using es6 in node.js. brief quote top answer:

it seems harmony enables new ecma features in language. reason file won't run without harmony because app.js using non-backward compatible features new ecma standard (like block scoping, proxies, sets, maps, etc.)

to explain why might seeing 3 dots, see this question:

so basically, opened node in interactive terminal, , typed node example.js, trying run if javascript. shows 3 dots because not valid javascript code, , waiting type more code might make valid.

output

the above output. ran in terminal (using 0.12.21):

> $ node --harmony > (() => 0) === (() => 0) > false

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