Сервис получения графика через chartjs-image

chart/.gitignore

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+node_modules/

chart/main.js

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+const ChartJSImage = require('chart.js-image');
+const pool = require('../database/postgresql.js');
+
+async function gen_chart(from_currency, conv_currency, start_date, end_date) {
+    const data = await pool.query('SELECT date, rate FROM currency WHERE ' +
+        '(date BETWEEN $3 AND $4) AND from_currency = $1 AND conv_currency = $2 ORDER BY date ', [
+        from_currency.toUpperCase(),
+        conv_currency.toUpperCase(),
+        start_date,
+        end_date
+    ]);
+
+    if (!data) return new Error('Missing data');
+
+    const date = [];
+    const rate = [];
+
+    for (let i = 0; i < data.rows.length; i++) {
+        date.push(data.rows[i].date.toLocaleDateString());
+        rate.push(data.rows[i].rate);
+    }
+
+    const chart = ChartJSImage().chart({
+        type: 'line',
+        options: {
+              title: {
+                  display: true,
+                  text: `${from_currency} / ${conv_currency}`,
+              },
+        },
+        data: {
+            labels: date,
+            datasets: [
+                {
+                    label: 'rate',
+                    borderColor: rate[rate.length-2] < rate[rate.length-1] ? 'rgb(24, 218, 39)' : 'rgb(243, 85, 50)',
+                    backgroundColor:  rate[rate.length-2] < rate[rate.length-1] ? 'rgb(36, 175, 47)' : 'rgb(218, 56, 24)',
+                    data: rate,
+                    borderWidth: 2,
+                },
+            ],
+        },
+        scales: {
+           xAxes: [
+               {
+                   scaleLabel: {
+                       display: true,
+                       labelString: 'Day'
+                   },
+               },
+           ],
+            yAxes: [
+                {
+                    stacked: false,
+                    scaleLabel: {
+                        display: true,
+                        labelString: 'Rate'
+                    },
+                },
+            ],
+        },
+    }).width(1000).height(1000);
+
+    return chart.toURL();
+}
+
+module.exports = { gen_chart }

chart/package-lock.json

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+{
+  "name": "chart",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "chart",
+      "version": "1.0.0",
+      "license": "GPL-3.0-or-later",
+      "dependencies": {
+        "chart.js-image": "^6.1.3"
+      }
+    },
+    "node_modules/chart.js-image": {
+      "version": "6.1.3",
+      "resolved": "https://registry.npmjs.org/chart.js-image/-/chart.js-image-6.1.3.tgz",
+      "integrity": "sha512-K+h0dc/Wf/Dk5CWKrV7xxS7ozONCiQ73XL+QStBxUpgABzSblJwQe/R6X1RWxY2Z/G8OhKsPFB0HC7bwiCmB2w==",
+      "license": "MIT",
+      "dependencies": {
+        "javascript-stringify": "2.0.1",
+        "node-fetch": "2.6.0"
+      },
+      "engines": {
+        "node": ">12"
+      }
+    },
+    "node_modules/javascript-stringify": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/javascript-stringify/-/javascript-stringify-2.0.1.tgz",
+      "integrity": "sha512-yV+gqbd5vaOYjqlbk16EG89xB5udgjqQF3C5FAORDg4f/IS1Yc5ERCv5e/57yBcfJYw05V5JyIXabhwb75Xxow==",
+      "license": "MIT"
+    },
+    "node_modules/node-fetch": {
+      "version": "2.6.0",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.6.0.tgz",
+      "integrity": "sha512-8dG4H5ujfvFiqDmVu9fQ5bOHUC15JMjMY/Zumv26oOvvVJjM67KF8koCWIabKQ1GJIa9r2mMZscBq/TbdOcmNA==",
+      "license": "MIT",
+      "engines": {
+        "node": "4.x || >=6.0.0"
+      }
+    }
+  }
+}

chart/package.json

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+{
+  "name": "chart",
+  "version": "1.0.0",
+  "main": "main.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/redume/kekkai.git"
+  },
+  "author": "Redume",
+  "license": "GPL-3.0-or-later",
+  "bugs": {
+    "url": "https://github.com/redume/kekkai/issues"
+  },
+  "homepage": "https://github.com/redume/kekkai#readme",
+  "description": "A service for creating graphs",
+  "dependencies": {
+    "chart.js-image": "^6.1.3"
+  }
+}