test.js

let gjsProject = {
    "gjsProject": {
        "project": [],
        "published": "No",
        "title": "title"
    }
}

var feed = {
    'hanny': {"assets":[{"type":"image","src":"https://via.placeholder.com/350x250/78c5d6/fff","unitDim":"px","height":0,"width":0},{"type":"image","src":"https://via.placeholder.com/350x250/459ba8/fff","unitDim":"px","height":0,"width":0},{"type":"image","src":"https://via.placeholder.com/350x250/79c267/fff","unitDim":"px","height":0,"width":0},{"type":"image","src":"https://via.placeholder.com/350x250/c5d647/fff","unitDim":"px","height":0,"width":0},{"type":"image","src":"https://via.placeholder.com/350x250/f28c33/fff","unitDim":"px","height":0,"width":0},{"type":"image","src":"https://via.placeholder.com/350x250/e868a2/fff","unitDim":"px","height":0,"width":0},{"type":"image","src":"https://via.placeholder.com/350x250/cc4360/fff","unitDim":"px","height":0,"width":0}],"styles":[{"selectors":[{"name":"gjs-row","private":1}],"style":{"display":"flex","justify-content":"flex-start","align-items":"stretch","flex-wrap":"nowrap","padding":"10px"}},{"selectors":[{"name":"gjs-row","private":1}],"style":{"flex-wrap":"wrap"},"mediaText":"(max-width: 768px)","atRuleType":"media"},{"selectors":[{"name":"gjs-cell","private":1}],"style":{"min-height":"75px","flex-grow":"1","flex-basis":"100%"}}],"pages":[{"frames":[{"component":{"type":"wrapper","stylable":["background","background-color","background-image","background-repeat","background-attachment","background-position","background-size"],"attributes":{"id":"i4z7"},"head":{"type":"head"},"docEl":{"tagName":"html"}},"id":"lzfWB2aoBcOEcKnh"}],"id":"vHTAW2qbFQVExGek"}],"symbols":[],"dataSources":[]}
}

gjsProject.gjsProject.project.push(feed);
gjsProject.gjsProject.project.push(feed);

console.log(gjsProject.gjsProject.project)