Unable to update protractor config at runtime - selenium-webdriver

Question

I am trying to update protractor config on the run time, because spec file are being read from external excel file.
Below is my config:
export let config = {
allScriptsTimeout: RunConfig.allScriptsTimeout,
capabilities: {
browserName: RunConfig.browser
},
directConnect: true,
baseUrl: RunConfig.baseUrl,
framework: RunConfig.framework,
jasmineNodeOpts: {
showColors: true,
defaultTimeoutInterval: RunConfig.defaultTimeoutInterval,
print: function () {
}
},
onPrepare() {
bot.fullScreen();
Xlsx.readExcel();
jasmine.getEnv().addReporter(new SpecReporter({ spec: { displayStacktrace: true } }));
},
beforeLaunch() {
let spec = new Promise((resolve) => {
resolve({
specs: Xlsx.readSpecs()
});
});
},
resultJsonOutputFile: RunConfig.resultFile
}
According to this it should update config in beforeLaunch
==========================
ReadSpec Function
readSpecs() {
fs.readFile(RunConfig.runManager, (err, buf) => {
if(!err && buf) {
let wb = XLSX.read(buf, { type: 'buffer' });
let sheet = wb.Sheets[sheetNames.specs]; //reading specs
let specArr = XLSX.utils.sheet_to_json(sheet);
let spec;
specArr.forEach(element => {
spec.push(element.spec);
});
return spec;
} else {
return [];
}
});
}

Answer 1

I add explanation inline:
XLSX = require('xlsx');
// change readSpecs() to sync style
readSpecs() {
let wb = XLSX.readFile(RunConfig.runManager);
let sheet = wb.Sheets[sheetNames.specs]; //reading specs
let specArr = XLSX.utils.sheet_to_json(sheet);
let spec;
specArr.forEach(element => {
spec.push(element.spec);
});
return spec;
}
export let config = {
// specify value for `specs`, and it require `Xlsx.readSpecs()`
// does not return promise-like object.
specs: Xlsx.readSpecs(),
onPrepare() {
bot.fullScreen();
// you need to move Xlsx.readExcel(); to the top
// when protractor run into onPrepare() function,
// it means protractor runner had accepted your passed-in config
// the runner won't accept any changes to the config once it accepted.
// Xlsx.readExcel();
jasmine.getEnv().addReporter(new SpecReporter({
spec: {
displayStacktrace: true
}
}));
},
// beforeLaunch() is unnecessary
// beforeLaunch() {
// let spec = new Promise((resolve) => {
// resolve({
// specs: Xlsx.readSpecs()
// });
// });
// },
};
beforeLaunch() can't change the config yet. There is no hooks can change the config before protractor read it. The only way is to give a pre-know value to specs and not allow promise-like value.
If your Xlsx.readExcel() or Xlsx.readSpecs() return promise, you have to use another way to implement it.

Answer 2

You aren't using the local variable spec for anything in the beforeLaunch function. The example in the link you posted is returning the resolved promise. You need to get rid of the local variable and return the promise like this:
beforeLaunch() {
return new Promise((resolve) => {
resolve({
specs: Xlsx.readSpecs()
});
});
}