I have received result from Raspberry Pi as Text format and I want to use these text to insert into MongoDB as key-pair value or JSON for my Node.js Application. However, I am quite new with JavaScript and trying to figure out the solution. Please help me if you have any suggestion, Thank you very much.
Example:
//Text from Raspberry Pi
1, 2300,450
2, 2200, 920
3, 3400, 440
and I want it to be
[
{
person: 1,
x position: 2300,
y position: 450
},
{
person: 2,
x position: 2200,
y position: 920
},
{
person: 3,
x position: 3400,
y position: 440
}
]
CodePudding user response：
You can first create array from the text by using split method and then convert the input array to the array of the object
- Split on new line character
/nto get the lines - Split on the comma and space
,to get all the elements - Loop over the array and convert array element to object
Code snippet
let input = `1, 2300, 450
2, 2200, 920
3, 3400, 440`;
let linesArr = input.split(/\n/);
let elArray = linesArr.map((line) => line.split(', '))
let result = elArray.map((el) => {
return {
"person": parseInt(el[0]),
"x_position": parseInt(el[1]),
"y_position": parseInt(el[2])
}
})
console.log(result)CodePudding user response：
You can transform your string into an array, use an array to store the exact name of your keys and then through .reduce create your new array.
const input = '1, 2300, 450, 2, 2200, 920, 3, 3400, 440';
const keys = ['person', 'x position', 'y position'];
let obj = {};
let counter = 0;
const result = input.split(',').reduce((acc, x) => {
obj[keys[counter]] = x.trim();
counter
if (counter % 3 === 0) {
acc.push(obj)
counter = 0;
obj = {};
}
return acc;
}, [])
console.log(result)CodePudding user response：
Use split and map
let txt = `
1, 2300,450
2, 2200, 920
3, 3400, 440`;
let split = txt.split(/\n/);
let filter = split.filter(e => e != '');
let map = filter.map(function(f1) {
let obj = {}
obj['person'] = parseInt(f1.split(',')[0].trim(), 10);
obj['x position'] = parseInt(f1.split(',')[1].trim(), 10);
obj['y position'] = parseInt(f1.split(',')[2].trim(), 10);
return obj;
});
console.log(map);CodePudding user response：
const fs = require("fs");
let data = fs.readFileSync("fs.txt", 'utf8');
let splitedData = data.split(",");
let final = [];
let person = splitedData[0];
let length = splitedData.length;
console.log(splitedData);
for(i=1;i<length; i=i 2){
let yposper;
let xposition = splitedData[i];
let yposition;
if(i!=(length-2)){
yposper = splitedData[i 1].split("\r\n");
yposition = yposper[0];
} else{
yposition = splitedData[i 1];
}
final.push({
person: person,
xposition: xposition.trim(),
yposition: yposition.trim()
});
person = i!=(length-2) ? yposper[1] : null;
}
console.log(final);
CodePudding user response：
My own suggestion would be:
// creating a named function, as a constant, since the function isn't
// expected to be modified by code; this function is defined using
// Arrow syntax, and passes in the Event Object - from the (later)
// use of EventTarget.addEventListener() - to the function body:
const getResults = (evt) => {
// here we retrieve the element to which the function was bound
// with EventTarget.addEventListener():
let button = evt.currentTarget,
// from the <button> element we navigate - with Element.closest()
// to the closest ancestor-element that matches the supplied CSS
// selector; note that if no such element is found then this
// will return null. So if you can't be sure the element will
// exist, sanity-check the variable before use:
ancestor = button.closest('li'),
// from the ancestor we retrieve the <textarea> element, using
// Element.querySelector(), which finds the first element
// inside of the ('ancestor', <li>) Element that matches the
// selector; again: if no such element is found, this will
// return null:
textarea = ancestor.querySelector('textarea'),
// this is my habitual practice, but effectively we try to
// retrieve the value property of the <textarea> element, if
// that doesn't have a value, or returns a falsey value,
// we retrieve the text-content instead:
entry = textarea.value || textarea.textContent,
// here we split the value/text-content on new-line characters,
// using String.protoype.split() and passing in a regular
// expression literal (/<regex sequence>/); which returns an
// Array. We then use Array.prototype.reduce() to return a new
// Array based on the passed-in Array:
result = entry.split(/\n/).reduce(
// here we pass in the accumulator ('acc', the Array we're working
// to produce on each iteration through this Array) and the
// Array-entry ('curr'):
(acc, curr) => {
// here we split the current ('curr') Array-value which is a String,
// again using String.prototype.split() and a regular expression-literal;
// this regular expression matches a comma followed by zero-or-more white-
// space characters (tabs, space, etc...); we expect this String to return
// a three part Array and we know the order; so we can use destructuring
// assignment to define person as equal to the first Array-element,
// posX to the second and posY to the third. If there are more
// Array elements returned those will be unallocated:
let [person, posX, posY] = curr.split(/,\s*/);
// I can't remember the term for this, but it's effectively a shorthand;
// but we use Array.prototype.push() to add an Object to the
// accumulator Array; this Object passes in the variables and those variables
// become both the name of the property (so the variable 'person' becomes both
// the property 'person' and sets the value of that property to the value of
// the variable):
acc.push({
person,
posX,
posY,
});
// we return the accumulator to continue working on it in the next iteration:
return acc;
// and here we pass in an empty Array-literal to act as the accumulator:
}, []);
// logging the result to the console:
console.log(result);
},
// here we find all <button> elements with a 'type' attribute equal to 'button', using
// document.querySelectorAll() to obtain a NodeList:
buttons = document.querySelectorAll('button[type=button]');
// here we use NodeList.prototype.forEach() to iterate over the <button> elements:
buttons.forEach(
// passing in a reference to the current Node of the NodeList over which we're iterating
// to the Arrow function-body, and using EventTarget.addEventListener() to bind the
// getResults() function as the event-handler for the 'click' event, this also passes
// the Event Object to the named function:
(btn) => btn.addEventListener('click', getResults)
);*,
::before,
::after {
box-sizing: border-box;
font-family: sans-serif;
font-size: 16px;
font-weight: 400;
line-height: 1.5;
margin: 0;
padding: 0;
}
ul,
li {
list-style-type: none;
padding: 1em;
}
li {
display: flex;
flex-direction: column;
gap: 0.5em;
justify-content: space-between;
}
textarea {
min-height: 40vmin;
width: 100%;
}<ul>
<li >
<textarea>1, 2300,450
2, 2200, 920
3, 3400, 440</textarea>
<button type="button">format</button>
</li>
</ul>This, of course, relies upon the result being returned from the Pi with each entry on a new line; if this can't be guaranteed, or the Pi returns entries in a String without new-lines, the following may be preferred:
// this is much the same as above, except that we have no line-separators (though this
// may not be relevant to your situation):
const getResults = (evt) => {
let button = evt.currentTarget,
ancestor = button.closest('li'),
textarea = ancestor.querySelector('textarea'),
entry = textarea.value || textarea.textContent,
// here we split the retrieved value/text-content of the <textarea> on the ','
// (comma) characters; and then iterate over the returned Array using an
// Arrow function, to trim any leading, and/or trailing, white-space from
// each Array entry:
haystack = entry.split(/,/).map((v) => v.trim()),
// here we use Array.prototype.reduce() to create the Array to return:
result = haystack.reduce(
// we again use the accumulator ('acc'), and the current ('curr') array-value,
// but we also pass in the index of the current Array-element:
(acc, curr, index) => {
// if the remainder left after dividing the current index by 3 is
// exactly 0 (true for 0, 3, 6, 9...):
if (index % 3 === 0) {
// we use destructuring assignment to assign the named
// variables ('person', 'posX', 'posY') to the result of
// calling Array.splice() on a copy of the 'haystack'
// Array (copied using spread syntax ('...') and an Array-literal
// ('[]'); this removes n (here, 3) elements from the copy, starting at
// the Array index 'index', and returns the removed Array elements:
let [person, posX, posY] = [...haystack].splice(index, 3);
// here we - again - push an Object, defined using the same shorthand
// as above, to the accumulator Array:
acc.push({
person,
posX,
posY
});
}
return acc
}, []);
// loggin the result variable:
console.log(result);
},
buttons = document.querySelectorAll('button[type=button]');
buttons.forEach(
(btn) => btn.addEventListener('click', getResults)
);*,
::before,
::after {
box-sizing: border-box;
font-family: sans-serif;
font-size: 16px;
font-weight: 400;
line-height: 1.5;
margin: 0;
padding: 0;
}
ul,
li {
list-style-type: none;
padding: 1em;
}
li {
display: flex;
flex-direction: column;
gap: 0.5em;
justify-content: space-between;
}
textarea {
min-height: 40vmin;
width: 100%;
}<ul>
<li >
<textarea>1, 2300,450, 2, 2200, 920,3, 3400, 440</textarea>
<button type="button">format</button>
</li>
</ul>References: