JS script for recount values of html table

Jahspear
April 8, 2023
126 views
3 votes
3 Answers

I have a table in my html file.

<table class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th>timestamp</th>
      <th>cid1</th>
      <th>cid2</th>
      <th>cid3</th>
      <th>cid4</th>
      <th>cid5</th>
      <th>cid6</th>
      <th>cid7</th>
      <th>cid8</th>
      <th>cid9</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>2023-04-08 15:39:21</td>
      <td>125</td>
      <td>4342&</td>
      <td>73645</td>
      <td>246</td>
      <td>4624</td>
      <td>1137504</td>
      <td>62467</td>
      <td>16596</td>
      <td>302207.827877119</td>
    </tr>
    <tr>
      <td>2023-04-08 15:39:21</td>
      <td>62462</td>
      <td>462436</td>
      <td>462436</td>
      <td>2462436</td>
      <td>2</td>
      <td>4924872</td>
      <td>46246</td>
      <td>16619</td>
      <td>1769805.989015266</td>
    </tr>
  </tbody>
</table>

This file created by my python script and I want to add inside js script for recount table without call my backend. Inside data follow the formulas: cid6 = cid4*cid5 and cid9=cid6/cid7*cid8

I want to paste in my html input form for new_cid4 value which must to replace each cid4 values in the table only for rows where ‘cid4’ < ‘new_cid4’. As result I want to recount values of columns cid6, cid9. Аnd very good if rows where cid4 > new_cid4 will be hided.

I’m pythonist and can’t to make this js script myself. May be JS masters can help me?

Tags: html javascript

Answers

Basically, you need to add an event listener to the element in question.

First, query elements from the document using document.querySelector() (assuming you have one <input> and one <button>; I made a snippet below for your reference):

<input type="number">
<button>Submit</button>

const input = document.querySelector('input');
const button = document.querySelector('button');

Then, add an event listener:

button.addEventListener('click', () => {
  // Retrieve the value of <input>. This value is a string.
  const new_cid4 = input.value;

  // Get all rows in an array-like.
  const rows = document.querySelectorAll('tbody tr');

  // Iterate over each row
  for (const row of rows) {
    // Shortcut lambdas
    const cell = index => row.children[index];
    const cellValue = index => cell(index).textContent;

    const cid4 = cellValue(4);

    // Convert to number explicitly since we're comparing.
    if (Number(cid4) >= Number(new_cid4)) {
      // Add an inline 'display: none' for the row.
      row.style.display = 'none';
      continue;
    }

    // Remove inline 'display', if any.
    row.style.removeProperty('display');

    // Calculate new cell values.
    // Note that JS automatically convert strings to numbers when multiplying / dividing.
    // (i.e. no need to use Number() explicitly)
    cell(4).textContent = new_cid4;
    cell(6).textContent = new_cid4 * cellValue(5);
    cell(9).textContent = cellValue(6) / cellValue(7) * cellValue(8);
  }
});

Try it:

// Demo only
addRandomData();

const input = document.querySelector('input');
const button = document.querySelector('button');

button.addEventListener('click', () => {
  const new_cid4 = input.value;

  const rows = document.querySelectorAll('tbody tr');

  for (const row of rows) {
    const cell = index => row.children[index];
    const cellValue = index => cell(index).textContent;

    const cid4 = cellValue(4);

    // Unary '+' is a shortcut for Number().
    if (+cid4 >= +new_cid4) {
      row.style.display = 'none';
      continue;
    }
    
    row.style.removeProperty('display');

    cell(4).textContent = new_cid4;
    cell(6).textContent = new_cid4 * cellValue(5);
    cell(9).textContent = (
      cellValue(6) / cellValue(7) * cellValue(8)
    ).toFixed(2); // Decimal places

    // Demo only
    blink(row);
  }
});


/* Demo only */

function addRandomData() {
  const tbody = document.querySelector('tbody');

  const max = 2 + Math.random() * 10 | 0;

  for (let i = 0; i < max; i++) {
    const row = document.createElement('tr');

    row.appendChild(createCell('2023-05-08 15:39:21'));

    for (let j = 0; j < 9; j++) {
      row.appendChild(
        createCell(Math.random() * 1e3 | 0)
      );
    }

    const calculator = cellCalculatorFromRow(row)
    calculator(6, row => row[4] * row[5]);
    calculator(9, row => row[6] / row[7] * row[8]);

    tbody.appendChild(row);
  }
}

function createCell(text = '') {
  const cell = document.createElement('td');
  cell.textContent = text;
  return cell;
}

function cellCalculatorFromRow(row) {
  const cellValues = new Proxy(row, {
    get(target, property) {
      return +target.children[property].textContent;
    }
  });
  return function(index, callback) {
    row.children[index].textContent = +callback(cellValues).toFixed(2);
  }
}

function blink(row) {
  row.animate([
    { background: '#ff0' },
    { background: '#fff' }
  ], 700);
}

table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}

#form {
  margin: 1em 0;
}

<table class="dataframe">
  <thead>
    <tr style="text-align: right">
      <th>timestamp</th>
      <th>cid1</th>
      <th>cid2</th>
      <th>cid3</th>
      <th>cid4</th>
      <th>cid5</th>
      <th>cid6</th>
      <th>cid7</th>
      <th>cid8</th>
      <th>cid9</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>2023-04-08 15:39:21</td>
      <td>125</td>
      <td>4342</td>
      <td>73645</td>
      <td>246</td>
      <td>4624</td>
      <td>624</td>
      <td>62467</td>
      <td>16596</td>
      <td>0.65</td>
    </tr>
    <tr>
      <td>2023-04-08 15:39:21</td>
      <td>62462</td>
      <td>462436</td>
      <td>462436</td>
      <td>2462436</td>
      <td>2436246</td>
      <td>462436</td>
      <td>46246</td>
      <td>16619</td>
      <td>0.51</td>
    </tr>
  </tbody>
</table>

<div id="form">
  <input type="number">
  <button>Submit</button>
</div>

Version with html input. It recalculate values and hides rows where this condition is not met cid4 <= new_cid4. It also gets all the table values and create the array of objects out of them.

const updateRow = (new_cid4, rowData, reset = false) => {
    const { cid1, cid2, cid3, cid5, cid7, cid8 } = rowData;
    let { cid4, cid6, cid9 } = rowData;
    if (!reset) cid4 = cid4 <= new_cid4 ? new_cid4 : cid4;
    cid6 = cid4 * cid5;
    cid9 = (cid6 / cid7) * cid8;
    return { cid1, cid2, cid3, cid4, cid5, cid6, cid7, cid8, cid9,};
};

const updateRowDOM = (row, rowData, hideRow = false) => {
    row.querySelector('td:nth-child(5)').textContent = rowData.cid4;
    row.querySelector('td:nth-child(7)').textContent = rowData.cid6;
    row.querySelector('td:nth-child(10)').textContent = rowData.cid9;
    row.classList.toggle('hidden', hideRow);
};

const cid4Input = document.getElementById('cid4Input');
const updateButton = document.getElementById('updateButton');
const rows = document.querySelectorAll('.dataframe tbody tr');


let new_cid4 = 0;
let data = [...rows].map((row) => {
    const timestamp = row.querySelector('td:first-child').textContent;
    const rowData = [...row.querySelectorAll('td:nth-child(n+1)')].reduce(
        (acc, td, index) => ({...acc,[`cid${index}`]: parseFloat(td.textContent.replace(',', '.')) }), {}
    );
    const updatedRowData = updateRow(new_cid4, rowData);

    return {
        timestamp,
        ...updatedRowData,
    };
});

let defaultData = [...data];

const handleUpdate = (new_cid4, data, reset = false) => {
    return data.map((rowData, index) => {
        const row = rows[index];
        const hideRow = !reset ? rowData.cid4 >= new_cid4 : false;

        const updatedRowData = updateRow(new_cid4, rowData, reset);
        updateRowDOM(row, updatedRowData, hideRow);

        return {timestamp: rowData.timestamp,  ...updatedRowData,
        };
    });
};

updateButton.addEventListener('click', () => {
    const new_cid4 = Number(cid4Input.value);
    data = new_cid4 ?
        handleUpdate(new_cid4, data, false) :
        handleUpdate(0, defaultData, true);
});

.dataframe {
  border-collapse: collapse;
  width: 100%;
  border: 1px solid #dee2e6;
 }
  th,td {
   padding: 0.5rem;
   text-align: left;
   border: 1px solid #dee2e6;
 }
  
   th {
    font-weight: bold;
  }
  .controls{
    padding: 0 0 20px 0;
  }
  .hidden{
     display:none;
 }

<div id="wrap">
<div class="controls">
 <input type="number" id="cid4Input">
  <button id="updateButton">Update cid4</button>
</div>
   <table class="dataframe">
 <thead>
   <tr style="text-align: right;">
     <th>timestamp</th>
     <th>cid1</th>
     <th>cid2</th>
     <th>cid3</th>
     <th>cid4</th>
     <th>cid5</th>
     <th>cid6</th>
     <th>cid7</th>
     <th>cid8</th>
     <th>cid9</th>
   </tr>
 </thead>
 <tbody>
   <tr>
     <td>2023-04-08 15:39:21</td>
     <td>125</td>
     <td>4342&</td>
     <td>73645</td>
     <td>246</td>
     <td>4624</td>
     <td>1137504</td>
     <td>62467</td>
     <td>16596</td>
     <td>302207,827877119</td>
   </tr>
   <tr>
     <td>2023-04-08 15:39:21</td>
     <td>62462</td>
     <td>462436</td>
     <td>462436</td>
     <td>2462436</td>
     <td>2</td>
     <td>4924872</td>
     <td>46246</td>
     <td>16619</td>
     <td>1769805,989015266</td>
   </tr>
 </tbody>
   </table>
   
   </div>

First, you need to determine th cell indices, and then make a calculation tbody tr based on them.

new_cid4.oninput = function() {
  const value = this.value ?? Number(this.value);
  const tables = document.querySelectorAll('.dataframe');
  
  tables.forEach(table => {
    /* get cels indexes */
    const cels = [...table.querySelectorAll('th')].reduce((prev, current, index) => {
     prev[current.textContent] = index;
     return prev;
    }, {})
    
    /* cid4 */
    if (cels.cid4) {
     table.querySelectorAll(`td:nth-child(${cels.cid4 + 1})`).forEach(el => {
      if (!el.dataset.initialValue) {
        el.dataset.initialValue = Number(el.textContent);
      }
      const tr = el.closest('tr');
      tr.style.display = 'table-row';
      /* restore */
      if (value === '') {
        el.textContent = el.dataset.initialValue;
        return;
      }
      const val = Number(el.textContent);
      if (val <= value) {
        el.textContent = value;
      } else {
        tr.style.display = 'none';
      }
     })
    }
    
    table.querySelectorAll('tbody tr').forEach(tr => {
     /* cid6 = cid4*cid5 */
     if (cels.cid6, cels.cid4, cels.cid5) {
      const cid4 = getCell(cels.cid4);
      const cid5 = getCell(cels.cid5);
      const cid6 = getCell(cels.cid6);
      cid6.textContent = Number(cid4.textContent) * Number(cid5.textContent);
     }
     /* cid9=cid6/cid7*cid8 */
     if (cels.cid9, cels.cid6, cels.cid7, cels.cid8) {
      const cid9 = getCell(cels.cid9);
      const cid6 = getCell(cels.cid6);
      const cid7 = getCell(cels.cid7);
      const cid8 = getCell(cels.cid8);
      cid9.textContent = Number(cid6.textContent) / Number(cid7.textContent) * Number(cid8.textContent);
     }
     function getCell(index) {
      return tr.querySelector(`td:nth-child(${index + 1})`);
     }
    })
  })
}

.dataframe {
  border-collapse: collapse;
  border-spacing: 0;
  width: 100%;
}

.dataframe td {
  padding: 5px;
  border: solid 1px #ccc;
}

<table class="dataframe">
  <thead>
   <tr style="text-align: right;">
    <th>timestamp</th>
    <th>cid1</th>
    <th>cid2</th>
    <th>cid3</th>
    <th>cid4</th>
    <th>cid5</th>
    <th>cid6</th>
    <th>cid7</th>
    <th>cid8</th>
    <th>cid9</th>
   </tr>
  </thead>
  <tbody>
   <tr>
    <td>2023-04-08 15:39:21</td>
    <td>125</td>
    <td>4342</td>
    <td>73645</td>
    <td>246</td>
    <td>4624</td>
    <td>1137504</td>
    <td>62467</td>
    <td>16596</td>
    <td>302207.827877119</td>
   </tr>
   <tr>
    <td>2023-04-08 15:39:21</td>
    <td>62462</td>
    <td>462436</td>
    <td>462436</td>
    <td>2462436</td>
    <td>2</td>
    <td>4924872</td>
    <td>46246</td>
    <td>16619</td>
    <td>1769805.989015266</td>
   </tr>
  </tbody>
</table>
<br><br>
<input type="number" id="new_cid4" placeholder="new_cid4">

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