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VisualizaçõesCarga útil dividida de JSON String
Recibo estas cadenas enormes a través de WebSocket:
[ "BTC-31DEC21-100000-P", "{\"data\":{\"bids\":{\"0.01\":{\"price\":0.01,\"volume\":66.2,\"exchange\":\"DER\"},\"5.0E-4\":{\"price\":5.0E-4,\"volume\":1.1,\"exchange\":\"DER\"},\"0.637\":{\"price\":0.637,\"volume\":8.4,\"exchange\":\"DER\"}},\"asks\":{\"0.664\":{\"price\":0.664,\"volume\":8.4,\"exchange\":\"DER\"}}},\"isMasterFrame\":true}" ]o
[ "BTC-31DEC21-36000-C", "{\"data\":[{\"price\":0.422,\"volume\":8.4,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.423,\"volume\":0.0,\"exchange\":\"DER\",\"side\":\"ASKS\"}],\"isMasterFrame\":false}" ]o
[ "BTC-31DEC21-60000-P", "{\"data\":[{\"price\":0.105,\"volume\":0.0,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.1055,\"volume\":28.7,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.106,\"volume\":7.6,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.1065,\"volume\":43.0,\"exchange\":\"DER\",\"side\":\"ASKS\"}],\"isMasterFrame\":false}" ] Quiero comprobar isMasterFrame
let payload = JSON.parse(messageString[1]); if (payload.hasOwnProperty("isMasterFrame")) { for (let i = 0; i < payload.pairs.length; i++) { let currentPair = payload.data[i] currentPair = currentPair.replace(/\0/g, ''); //Remove null chars if (currentPair.toUpperCase() != 'KILL') { props.onAddAvailablePair(currentPair); } } } else { // print some output with payload which holds "isMasterFrame":false }Cuando ejecuto el código me sale error:
TypeError: Cannot read properties of undefined (reading 'length') Los datos de un par interno: {\"price\":0.423,\"volume\":0.0,\"exchange\":\"DER\",\"side\":\"ASKS\"} deben dividirse e insertado en el bucle uno por uno
¿Sabes cómo puedo solucionar este problema?
·
Santiago Trujillo
3 Respostas
Responde à pergunta0
Problema
No tiene pairs de propiedades dentro del objeto de carga útil , por lo que no puede acceder a su length .
Solución
Debe iterar sobre la propiedad de data . Dado que la propiedad data también es un objeto, puede usar la función Object.keys() e iterar sobre sus subpropiedades.
let payload = JSON.parse(messageString[1]); if (payload.hasOwnProperty("isMasterFrame")) { for (let i = 0; i < Object.keys(payload.data).length; i++) { let current_property= payload.data[Object.keys(payload.data)[i]]; console.log(current_property); ...
·
Santiago Trujillo
Relatório
0
Sus datos tienen una estructura diferente cuando isMasterFrame es diferente. Tiene un objeto de bids y isMasterFrame asks true , mientras que es una matriz cuando isMasterFrame es falso.
const data1 = [ "BTC-31DEC21-100000-P", "{\"data\":{\"bids\":{\"0.01\":{\"price\":0.01,\"volume\":66.2,\"exchange\":\"DER\"},\"5.0E-4\":{\"price\":5.0E-4,\"volume\":1.1,\"exchange\":\"DER\"},\"0.637\":{\"price\":0.637,\"volume\":8.4,\"exchange\":\"DER\"}},\"asks\":{\"0.664\":{\"price\":0.664,\"volume\":8.4,\"exchange\":\"DER\"}}},\"isMasterFrame\":true}" ], data2 = [ "BTC-31DEC21-36000-C", "{\"data\":[{\"price\":0.422,\"volume\":8.4,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.423,\"volume\":0.0,\"exchange\":\"DER\",\"side\":\"ASKS\"}],\"isMasterFrame\":false}" ] data3 = [ "BTC-31DEC21-60000-P", "{\"data\":[{\"price\":0.105,\"volume\":0.0,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.1055,\"volume\":28.7,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.106,\"volume\":7.6,\"exchange\":\"DER\",\"side\":\"ASKS\"},{\"price\":0.1065,\"volume\":43.0,\"exchange\":\"DER\",\"side\":\"ASKS\"}],\"isMasterFrame\":false}" ]; const formatData = (data) => { return data.reduce((r, o) => { Object.entries(o).forEach(([k,v]) => { r[k] ??= []; r[k].push(v); }); return r; }, {}) } [data1, data2, data3].forEach(data => { const o = JSON.parse(data[1]); if(o.isMasterFrame) { const result = formatData(Object.values(o.data.bids)); console.log(result); } else { const result = formatData(o.data); console.log(result); } });
·
Santiago Trujillo
Relatório
0
Puede ejecutar el fragmento de código a continuación para verlo en funcionamiento. También he adjuntado una captura de pantalla de una consola que muestra la salida de valores.
// THIS IS AN ARRAY CONTAINING A JSON var messageString = [ "BTC-31DEC21-100000-P", "{\"data\":{\"bids\":{\"0.01\":{\"price\":0.01,\"volume\":66.2,\"exchange\":\"DER\"},\"5.0E-4\":{\"price\":5.0E-4,\"volume\":1.1,\"exchange\":\"DER\"},\"0.637\":{\"price\":0.637,\"volume\":8.4,\"exchange\":\"DER\"}},\"asks\":{\"0.664\":{\"price\":0.664,\"volume\":8.4,\"exchange\":\"DER\"}}},\"isMasterFrame\":true}" ]; // THE JSON IS AT INDEX '1' OF THE ARRAY SO WE PARSE IT let payload = JSON.parse(messageString[1]); // YOU CAN SEE THE PARSED JSON IN CONSOLE console.log(payload.data); // SINCE isMasterFrame IS EITHER TRUE OR FALSE, WE CAN TEST FOR IT WITHOUT USING hasOwnProperty // IF isMasterFrame IS UNDEFINED OR NOT IN THE JSON, THE ELSE BLOCK WILL EXECUTE AND NOT BREAK THE CODE if (payload.isMasterFrame) { console.log("1 payload.isMasterFrame: " + payload.isMasterFrame); // SINCE IT IS A JSON, WE HAVE TO LOOP THROUGH THE FIRST PART THIS WAY for (var key in payload.data) { if (payload.data.hasOwnProperty(key)) { console.log("key base: " + key + " -> " + payload.data[key]); // SINCE THE VALUE IS ALSO A JSON OF VALUES, WE LOOP THROUGH AGAIN for (var key_inner1 in payload.data[key]) { if (payload.data[key].hasOwnProperty(key_inner1)) { console.log("key inner1: " + key_inner1 + " -> " + payload.data[key][key_inner1]); // GETTING THE CURRENT PAIR let currentPair = payload.data[key][key_inner1]; console.log("CURRENT PAIR"); console.log(currentPair); /* currentPair = currentPair.replace(/\0/g, ''); //Remove null chars if (currentPair.toUpperCase() != 'KILL') { props.onAddAvailablePair(currentPair); } */ // SINCE THE VALUE IS ALSO A JSON OF VALUES, WE LOOP THROUGH AGAIN TO GET THE REAL VALUES for (var key_inner2 in payload.data[key][key_inner1]) { if (payload.data[key][key_inner1].hasOwnProperty(key_inner2)) { // NOW WE CAN DO WHAT WE NEED TO WITH THE ACTUAL VALUES console.log("key inner2: " + key_inner2 + " -> " + payload.data[key][key_inner1][key_inner2]); } } } } } } } else { console.log("2 payload.isMasterFrame: " + payload.isMasterFrame); } 
·
Santiago Trujillo
Relatório
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