NodeJS: How do I enable CHACHA20_POLY1305 in https?

I use NodeJS version 7.7.2. Here is my cipher definition:

ciphers: [
        "ECDHE-ECDSA-CHACHA20-POLY1305",
        "ECDHE-ECDSA-AES256-GCM-SHA384",
        "ECDHE-ECDSA-AES256-SHA",
        "!RC4",
        "!AES128"
    ].join(':')

My openssl version is 1.1.0e 16 Feb 2017

Here is what return from openssl ciphers -v 'ECDHE-ECDSA-CHACHA20-POLY1305' command:

ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=CHACHA20/POLY1305(256) Mac=AEAD

However, what return from www.ssllabs.com shows that my website only support AES256 cipher suits:

TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (0xc02c)   ECDH secp384r1 (eq. 7680 bits RSA)   FS  256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (0xc00a)   ECDH secp384r1 (eq. 7680 bits RSA)   FS 256

Did I do something wrong?

via Branya The Great