feat: function to load data from json and flattenJSON

4 files changed, 114 insertions, 59 deletions

diff --git a/src/lib/data.ts b/src/lib/data.ts
index dcc948b..9649d6d 100644
--- a/src/lib/data.ts
+++ b/src/lib/data.ts
@@ -1,3 +1,6 @@
+import { Frame } from '../index';
+import { isValidJSONObject } from '../helpers/arrayFunctions';
+
 /**
  * flattenArray - flattens a 2D into a single array
  * @param array: the array to be flattened
@@ -14,3 +17,42 @@ export function flatten(array: any[][]): any[] {
   }
   return flattenedArray;
 }
+
+/**
+ * fromJSON - converts a JSON string into a rowdata - framedata is a 2D array
+ * @param json: the JSON string to be converted
+ * @returns the rowdata
+ */
+export function fromJSON(this: Frame, json: any): Frame {
+  if (isValidJSONObject(json)) {
+    const header: string[] = [];
+    const rowdata: any[][] = [];
+    // loop through each row
+    for (let i = 0; i < json.length; i++) {
+      // get all the keys and store them in the header
+      for (const key in json[i]) {
+        if (!header.includes(key)) {
+          header.push(key);
+        }
+      }
+    }
+    // loop through each row
+    for (let i = 0; i < json.length; i++) {
+      // get the values of the keys present in the header, if the values are not present in the row, add null
+      const row: any[] = [];
+      for (let j = 0; j < header.length; j++) {
+        if (json[i][header[j]] !== undefined) {
+          row.push(json[i][header[j]]);
+        } else {
+          row.push(null);
+        }
+      }
+      rowdata.push(row);
+    }
+    this.rowdata = rowdata;
+    this.columns = header;
+    return this;
+  } else {
+    throw new Error('Invalid JSON');
+  }
+}
diff --git a/src/lib/display.ts b/src/lib/display.ts
index 6aeb029..c33df70 100644
--- a/src/lib/display.ts
+++ b/src/lib/display.ts
@@ -40,7 +40,7 @@ function getTable(
  * @throws Error if the frame is empty
  */
 export function show(this: Frame): void {
-  if (!this.rowdata.length) {
+  if (this.rowdata.length === 0) {
     throw new Error('Set data before printing');
   }
   const numberOfRows = this.rowdata.length;
@@ -74,7 +74,7 @@ export function show(this: Frame): void {
  * @throws Error if the frame is empty
  */
 export function head(this: Frame, n = 5): void {
-  if (!this.rowdata.length) {
+  if (this.rowdata.length === 0) {
     throw new Error('Set data before printing');
   }
   // Check if n is greater than the number of rows
@@ -95,7 +95,7 @@ export function head(this: Frame, n = 5): void {
  * @throws Error if the frame is empty
  */
 export function tail(this: Frame, n = 5): void {
-  if (!this.rowdata.length) {
+  if (this.rowdata.length === 0) {
     throw new Error('Set data before printing');
   }
   // Check if n is greater than the number of rows
diff --git a/src/lib/frame.ts b/src/lib/frame.ts
index 8ed1316..d257fb4 100644
--- a/src/lib/frame.ts
+++ b/src/lib/frame.ts
@@ -63,12 +63,16 @@ export function setHeader(rowdata: any[][], header: any[]): Array<string> {
  */
 
 export function generateHeader(rd: Array<any[]>): Array<string> {
-  const maxSizedArrayLength = rd.reduce((acc, curr) => {
-    return acc.length > curr.length ? acc : curr;
-  }).length;
-  const header: Array<string> = [];
-  for (let i = 0; i < maxSizedArrayLength; i++) {
-    header.push(`Column ${i + 1}`);
+  if (rd?.length) {
+    const maxSizedArrayLength = rd.reduce((acc, curr) => {
+      return acc.length > curr.length ? acc : curr;
+    }).length;
+    const header: Array<string> = [];
+    for (let i = 0; i < maxSizedArrayLength; i++) {
+      header.push(`Column ${i + 1}`);
+    }
+    return header;
+  } else {
+    return [];
   }
-  return header;
 }
diff --git a/src/lib/info.ts b/src/lib/info.ts
index 814992b..9338c75 100644
--- a/src/lib/info.ts
+++ b/src/lib/info.ts
@@ -17,58 +17,67 @@ export function getSize(rowdata: any[]): number {
  * @returns the type of data present in each column of the frame
  */
 export function info(this: Frame): void {
-  const info: Array<any[]> = [];
-  info.push(['#', 'Column Name', 'Types', 'Empty Values']);
-  let counter = 0;
-  const countDataTypes = {} as any;
-  this.columns.forEach((column: string, index: number) => {
-    // get all the types of data in the column, do not repeat the same type
-    let nullValuesPresentInRow = false;
-    const columnDataTypes = this.rowdata.map((row: any[]) => {
+  if (this.rowdata.length === 0) {
+    throw new Error('Frame is empty');
+  } else {
+    const info: Array<any[]> = [];
+    info.push(['#', 'Column Name', 'Types', 'Empty Values']);
+    let counter = 0;
+    const countDataTypes = {} as any;
+    this.columns.forEach((column: string, index: number) => {
+      // get all the types of data in the column, do not repeat the same type
+      let nullValuesPresentInRow = false;
+      const columnDataTypes = this.rowdata.map((row: any[]) => {
+        if (
+          row[index] === null ||
+          row[index] === undefined ||
+          row[index] === ''
+        ) {
+          nullValuesPresentInRow = true;
+        }
+        const currentType = String(typeof row[index]);
+        if (!Object.keys(countDataTypes).includes(currentType)) {
+          Object.assign(countDataTypes, { [currentType]: 1 });
+        } else {
+          const getKeyValue = <T, K extends keyof T>(obj: T, key: K): T[K] =>
+            obj[key];
+          const currentValue = getKeyValue(countDataTypes, currentType);
+          Object.assign(countDataTypes, { [currentType]: currentValue + 1 });
+        }
+        return typeof row[index];
+      });
+      const uniqueDataTypes = [...new Set(columnDataTypes)];
+      info.push([
+        counter,
+        column,
+        [...uniqueDataTypes],
+        nullValuesPresentInRow
+      ]);
+      counter++;
+    });
+    let dataTypesString = '';
+    // Iterate through the countDataTypes object and create a string of the data types
+    Object.keys(countDataTypes).forEach((key: string) => {
+      dataTypesString += `${key}(${countDataTypes[key]})`;
+      // check if the key is not the last key in the object
       if (
-        row[index] === null ||
-        row[index] === undefined ||
-        row[index] === ''
+        Object.keys(countDataTypes).indexOf(key) !==
+        Object.keys(countDataTypes).length - 1
       ) {
-        nullValuesPresentInRow = true;
-      }
-      const currentType = String(typeof row[index]);
-      if (!Object.keys(countDataTypes).includes(currentType)) {
-        Object.assign(countDataTypes, { [currentType]: 1 });
-      } else {
-        const getKeyValue = <T, K extends keyof T>(obj: T, key: K): T[K] =>
-          obj[key];
-        const currentValue = getKeyValue(countDataTypes, currentType);
-        Object.assign(countDataTypes, { [currentType]: currentValue + 1 });
+        dataTypesString += ', ';
       }
-      return typeof row[index];
     });
-    const uniqueDataTypes = [...new Set(columnDataTypes)];
-    info.push([counter, column, [...uniqueDataTypes], nullValuesPresentInRow]);
-    counter++;
-  });
-  let dataTypesString = '';
-  // Iterate through the countDataTypes object and create a string of the data types
-  Object.keys(countDataTypes).forEach((key: string) => {
-    dataTypesString += `${key}(${countDataTypes[key]})`;
-    // check if the key is not the last key in the object
-    if (
-      Object.keys(countDataTypes).indexOf(key) !==
-      Object.keys(countDataTypes).length - 1
-    ) {
-      dataTypesString += ', ';
-    }
-  });
 
-  console.log(`RangeIndex: ${this.size} elements, 0 to ${this.size - 1}`);
-  console.log(
-    `Shape: ${this.shape.split(' x ')[0].trim()} rows, ${this.shape
-      .split(' x ')[1]
-      .trim()} columns`
-  );
-  console.log(table(info));
-  // Remove the previous printed newline
-  process.stdout.write('\x1B[1A\x1B[2K');
-  console.log(`Data Types: ${dataTypesString}`);
-  console.log(`Memory Usage: ${sizeof(this)} bytes`);
+    console.log(`RangeIndex: ${this.size} elements, 0 to ${this.size - 1}`);
+    console.log(
+      `Shape: ${this.shape.split(' x ')[0].trim()} rows, ${this.shape
+        .split(' x ')[1]
+        .trim()} columns`
+    );
+    console.log(table(info));
+    // Remove the previous printed newline
+    process.stdout.write('\x1B[1A\x1B[2K');
+    console.log(`Data Types: ${dataTypesString}`);
+    console.log(`Memory Usage: ${sizeof(this)} bytes`);
+  }
 }