<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">Le 3 juin 2015 à 11:08, Axel Rauschmayer <<a href="mailto:axel@rauschma.de" class="">axel@rauschma.de</a>> a écrit :</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><a href="https://people.mozilla.org/~jorendorff/es6-draft.html#sec-array.prototype.concat" class="">https://people.mozilla.org/~jorendorff/es6-draft.html#sec-array.prototype.concat</a><div class=""><br class=""></div><div class="">I’m not seeing @@isConcatSpreadable being used as a property key anywhere in the spec.</div><div class=""><br class=""></div><div class="">Thanks!</div><div class=""><br class=""></div><div class="">Axel</div><div class=""><br class=""></div></div></div></blockquote><div><br class=""></div><div>Look at the IsConcatSpreadable abstract operation:</div><div><br class=""></div><div><a href="https://people.mozilla.org/~jorendorff/es6-draft.html#sec-isconcatspreadable" class="">https://people.mozilla.org/~jorendorff/es6-draft.html#sec-isconcatspreadable</a></div><div><br class=""></div><div>Note that, in absence of @@isConcatSpreadable property key, IsArray() is considered instead,</div><div>so that builtin objects and constructors defined in the spec do not need to use @@isConcatSpreadable in order to get the right semantics.</div><div><br class=""></div><div>—Claude</div></div></body></html>